The AUSCAN Voyage
Day 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16
The biological sampling component of the AUSCAN expedition into the Murray Canyons region has been a success, according to ANU’s Patrick De Deckker, who headed up the three-and-a-half day sampling program.
“In particular, we are very happy with the cores - especially the first core which was almost thirty-three metres in length. It has proved to be above our expectations,” he said.
Patrick explained that the first core collected provides an incredibly rich data source to unlock the climatic and oceanographic secrets of the past.
“This core is of an incredible quality,” he said.
“We were hoping perhaps to get a core that would provide a one million year record.
“This core covers a shorter period, but the information it contains is of an incredibly high quality. Our other cores look equally as good, but we have no idea of the age of them at this stage.”
The ANU team will finish the voyage with a huge amount of material, with well over 80 metres of core sediment. The first core was nearly 33 metres and was collected on the eastern flank of the Murray Canyons. The second, bent core was 7.5 metres, and the third (gravity) and fourth (piston) cores, from the western canyon flanks - 11 and 32 metres respectively. The third and fourth cores actually cover the same time period – but one is compacted, and one stretched meaning the information they contain is at different resolutions.
The last two cores also contained a lot of hydrogen sulfide, which came as a surprise to the team. Further investigation into the organic content will now take place.
“We didn’t think that the River Murray was shedding so much organic matter,” Patrick said.
“Most of the cores in the region don’t have a large amount of organic matter - most are in the range of only 2 or 3%. We hadn’t anticipated this.
“Further research will help us open the archive and find out exactly what this means,” he said.
Additional tests will reveal the chronology of the core. There are a variety of techniques to determine the time scale for each core, and the processes are expected to take some time.
An associate member of the ANU team, Tony Rathburn from Indiana State University , will be returning to the United States with quite a bit of sediment collected from the multicores. The material provides information from the very top layers of the sea-floor, and typically contains foraminifera – unicellular organisms usually less than one millimeter in size.
Tony has sectioned the multicore samples into ½ cm slices, and will mix the material with a chemical dye, rose Bengal , which stains living organisms pink. The stain will reveal the foraminifera - one of the most abundant organisms in the deep sea, the largest ecosystem on the planet. They are used extensively to assess palaeoceanographic and palaeoclimatologic change.
The multicore provides samples for the last few hundred years, and material from the multicores will be studied for pine and vine pollen which will give information about the arrival of Europeans to Australia . They will also be tested for charcoal, as the Europeans systematically burned the landscape in the early white settler period. If charcoal is detected, further study will be conducted on the longer cores which will provide more detailed information.
Sabine Schmidt from France participated in the first leg of the AUSCAN voyage from Fremantle to Hobart. Sabine is a specialist whose particular area of research is Proactiniun – the study of accumulation rates of material in the seafloor. Samples will be transported to France for this aspect of the research, and Sabine will report back to Patrick De Deckker with her findings.
Lachie McLeay from SARDI will be returning to Adelaide with a lot of material from the canyons. The conductivity, temperature and depth (CTD) returned a lot of valuable data that will be used to further understand this unique area. So far, seven CTD profiles have been collected.
The CTD showed some areas which recorded very high readings of chlorophyll, which relates to the presence of abundant algae. Algae are very important, as they form a principal food source for copepods which are in turn fed on by fish. The algal readings provide a good measurement of the organic productivity in the water column.
The team has also collected many sub-samples of water from the CTD for analysis of stable isotopes (carbon and oxygen). These particular elements do not decay over time, so provide a very useful record of past events. Water samples were taken to test for various trace metals. These results will help interpret analysis to be done on foraminifera from the cores. Hopefully the past sea-surface temperatures will be obtained from these analyses.
The benthic sled returned far less material than was originally anticipated. The material that was gathered will be sent to the SARDI laboratories where it will be distributed among experts in the Victoria and South Australian Museums for identification. SARDI will be responsible for the curation of the samples.
The plankton tows brought back a lot of material for Lachie McLeay. He is particularly interested in finding out about fish larvae in the region, especially where pilchards and blue mackerel might spawn. Closer research in the SARDI labs will reveal more, although initial testing has shown that many of the samples contain fish larvae.
Patrick De Deckker also has some plankton samples to look at - microscopic organisms that have calcareous shells.
“We want to find out more about what’s in the water column,” he said.
“Hopefully we may also compare our research with Baudin’s expedition two hundred years ago. Baudin’s team of researchers actually described some of the larger plankton. It will be a very interesting exercise.”
Day 14
Day 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16
The activity on board the ship has slowed as we get closer to the end of our voyage.
The sampling program is finished and we’re just doing the swath mapping now.
During the early hours of the morning, the German team retrieved a core off the coast at Albany. The first attempt hit very hard rock and bent the core very badly. It meant we spent more time surveying the area and the second attempt brought back a better core of about 8.70 metres. It has been sectioned and packed for transport back to Germany.
The biological and geological sampling component of the AUSCAN expedition into the Murray Canyons region has been a success, according to ANU’s Patrick De Deckker who headed up the three-and-a-half day sampling program.
“In particular, we are very happy with the cores - especially the first core which was almost thirty-three metres in length. It has proved to be above our expectations,” he said.
Patrick explained that the first core collected provided an incredibly rich data source to unlock the climatic and oceanographic secrets of the past.
“This core is of an incredible quality,” he said.
“We were hoping perhaps to get a core which would provide a one million year record. This core covers a shorter period, but the information it contains is of an incredibly high quality. Our other cores look equally as good, but we have no idea of the age of them at this stage.”
The ANU team will finish the voyage with a huge amount of material, with well over 80 metres of core sediment weighing over two tonnes. The first core was nearly 33 metres and was collected on the eastern flank of the Murray Canyons. The second, bent core was 7.5 metres, and the third (gravity) and fourth (piston) cores, from the western canyon flanks - 11 and 32 metres respectively. These third and fourth cores actually cover the same time period – but one is compacted, and one stretched meaning the information they contain is at different resolutions.
A final core was collected off the coast of Albany today and measured close to 12 metres. Again further testing will determine the age of the core, which will be undertaken by both the Australian and French research teams.
Cores three and four contained a lot of hydrogen sulfide, which came as a surprise to the team. Further investigation into the organic content will now take place.
“We didn’t think that the River Murray was shedding so much organic matter,” Patrick said.
“Most of the cores in the region don’t have a large amount of organic matter - most are in the range of only 2 or 3%. We hadn’t anticipated this.”
“Further research will help us open the archive and find out exactly what this means.”
Additional tests will reveal the chronology of the core. There are a variety of techniques to determine the time scale for each core, and these processes are expected to take some time.
An associate member of the ANU team, Tony Rathburn from Indiana State University , will be returning to the United States with quite a bit of sediment collected from the multicores. This material provides information from the very top layers of the sea-floor, and typically contains foraminifera – unicellular organisms usually less than one millimetre in size.
Tony has sectioned the multicore samples into ½ cm slices, and then will mix the material with a chemical dye, rose Bengal, which stains living organisms pink. The stain will reveal the foraminifera - one of the most abundant organisms in the deep sea, the largest ecosystem on the planet. They are used extensively to assess palaeoceanographic and palaeoclimatologic change.
The multicore provides samples for the last few hundred years, and material from the multicores will be studied for pine and vine pollen which will give information about the arrival of Europeans to Australia . They will also be tested for charcoal, as the Europeans systematically burned the landscape in the early white settler period. If charcoal is detected, further study will be conducted on the longer cores which will provide more detailed information.
It has been a busy voyage and I think everyone’s looking forward to some time on dry land in Fremantle. We arrive at about 11am on Wednesday and will then have customs to deal with before we can disembark.
I’m looking forward to seeing some shops!
Day 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16
The Marion Dufresne docks in Fremantle tomorrow, reaching the end of her ground-breaking 16 day voyage.
Over the two legs of the voyage, the ship has traveled about 9,000 kilometres, mapping approximately 70,000 square kilometres of the sea floor - all within three weeks. During the course of the voyage, scientists gathered information from the ocean and sea floor at a variety of depths to learn about the region’s biology, geology and evolutionary history.
“During the course of the voyage we have been able to fill in many of the gaps in our knowledge of this area, and this new information will be added to the data we have collected in previous surveys,” Peter Hill, from Geoscience Australia, said.
“We have collected a great deal of detailed and high quality data. Shortly we will be producing some fantastic colour imagery and flythroughs of this part of Australia ’s undersea world. We will be integrating all of these new data with our existing data, including seismic information, to give us a fully three-dimensional picture of the canyons and continental margin.”
Geoscience Australia is currently investigating the continental margin, and the information gained through AUSCAN will help develop a model to explain the formation of the Southern Ocean when Australia and Antarctica were torn apart. We should be then able see how the two continents once fitted together.
In a previous survey, the Geoscience Australia team found areas with many peridotites – exposed huge crustal blocks in the sea bed - formed during early volcanic activity when Australia tore away from Antarctica . They have also mapped part of the Diamantina Fracture Zone, on the south-west of Western Australia , which is an area of very rough topography.
“We have now mapped the extensive canyon system, along the continental slope in detail,” Peter said.
“We can now trace the canyon systems from the continental shelf and see how they discharge sediment onto the abyssal plain 5000m below.”
Along the continental slope, the character of the canyons changes, depending on how sedimented the slope is. Some are very rugged and steep, with cliffs up to two kilometers high, dropping onto a flat and sedimented abyssal plain. Others are linear and very long, some over 100 kilometres. Some of the steeper canyons have a series of large holes along their courses up to several hundred metres deep and several kilometres across formed by scouring of the canyon floor.
“We didn’t know the Murray Canyons system would have these formations,” Peter said.
“All of this information will help us further understand the processes that occur in canyon development.”
I’m off to back my bags now and prepare for disembarkation tomorrow.
Day 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16
The historic AUSCAN voyage will draw to an end when the French research vessel Marion Dufresne docks in Fremantle today.
The second and main leg of the AUSCAN expedition, funded by the Australian National Oceans Office and the French Polar Institute, with contributions from Geoscience Australia, the South Australian Research and Development Institute and the Australian National University, left Hobart on February 18 to chart the seabed from the west coast of Tasmania to Fremantle, taking in a large section of Australia’s Exclusive Economic Zone and across the Great Australian Bight.
Australian scientists from Geoscience Australia, ANU and the South Australian Research and Development Institute were joined by scientific partners from the French Polar Institute and French, German and American research institutions.
Over the two legs of the voyage, the ship has traveled about 9,000 kilometres, mapping approximately 70,000 square kilometres of the sea floor all within three weeks. During the course of the voyage, scientists gathered information from the ocean and sea floor at a variety of depths to learn about the region's biology, geology and evolutionary history.
Submarine canyon systems have been mapped along the continental shelf off the coast of Victoria, across the Great Australian Bight and through to Fremantle, as well as off the west coast of Tasmania. One of the most interesting and exciting geological features charted are the Murray Canyons, into which the Murray River has shed sediments for millions of years.
The Marion Dufresne is equipped with state-of-the-art multibeam sonar and sub-bottom profiler equipment. It also carries magnetic and gravity measuring instruments and temperature and salinity readings have been collected along the way. For sediment sampling it has a giant piston corer, the largest of its kind on any research ship, as well as a variety of other geological, biological and oceanographic sampling tools.
Peter Hill from Geoscience Australia has led the seafloor swath mapping and geophysical program. Patrick De Deckker from the Australian National University headed up the biological and geological sampling program, and French and German teams also undertook sampling programs.
“During the course of the voyage we have been able to fill in many of the gaps in our knowledge of this area, and this new information will be added to the data we have collected in previous surveys,” said Peter Hill from Geoscience Australia. “We have collected a great deal of detailed and high quality data. Shortly we will be producing some fantastic colour imagery and flythroughs of this part of Australia’s undersea world. We will be integrating all of these new data with our existing data, including seismic information, to give us a fully three-dimensional picture of the canyons and continental margin.”
Geoscience Australia is currently investigating the continental margin, and the information gained through AUSCAN will help develop a model to explain the formation of the Southern Ocean when Australia and Antarctica were torn apart. We should be then able see how the two continents once fitted together.
In previous survey, the Geoscience Australia team found areas with many peridotites - exposed huge crustal blocks in the sea bed, formed during early volcanic activity when Australia tore away from Antarctica. They have also mapped part of the Diamantina Fracture Zone, on the south-west of Western Australia, which is an area of very rough topography.
“We now have mapped the extensive canyon system, along the continental slope in detail. We can now trace the canyon systems from the continental shelf and see how they discharge sediment onto the abyssal plain 5000m below,” said Peter Hill.
Along the continental slope, the character of the canyons changes, depending on how sedimented the slope is. Some are very rugged and steep, with cliffs up to two kilometers high, dropping onto a flat and sedimented abyssal plain. Others are linear and very long, some over 100 kilometres. Some of the steeper canyons have a series of large holes along their courses up to several hundred metres deep and several kilometres across formed by scouring of the canyon floor.
“We didn’t know the Murray Canyons system would have these formations,” said Peter Hill. “All of this information will help us further understand the processes that occur in canyon development.”
The biological and geological sampling component of the AUSCAN expedition into the Murray Canyons region has been a success, according to ANU’s Patrick De Deckker who headed up the three-and-a-half day sampling program. “In particular, we are very happy with the cores - especially the first core which was almost thirty-three metres in length. It has proved to be above our expectations,” he said.
Patrick explains that the first core collected provides an incredibly rich data source to unlock the climatic and oceanographic secrets of the past. “This core is of an incredible quality. We were hoping perhaps to get a core which would provide a one million year record. This core covers a shorter period, but the information it contains is of an incredibly high quality. Our other cores look equally as good, but we have no idea of the age of them at this stage.”
The ANU team will finish the voyage with a huge amount of material, with well over 80 metres of core sediment weighing over two tonnes. The first core was nearly 33 metres and was collected on the eastern flank of the Murray Canyons. The second, bent core was 7.5 metres, and the third (gravity) and fourth (piston) cores, from the western canyon flanks - 11 and 32 metres respectively. These third and fourth cores actually cover the same time period - but one is compacted, and one stretched meaning the information they contain is at different resolutions. A final core was collected off the coast of Albany and measured close to 12 metres. Again further testing will determine the age of the core, which will be undertaken by both the Australian and French research teams.
Cores three and four contained a lot of hydrogen sulfide, which came as a surprise to the team. Further investigation into the organic content will now take place. “We didn’t think that the River Murray was shedding so much organic matter. Most of the cores in the region don’t have a large amount of organic matter - most are in the range of only 2 or 3%. We hadn’t anticipated this,” he said. “Further research will help us open the archive and find out exactly what this means,” he said.
Additional tests will reveal the chronology of the core. There are a variety of techniques to determine the time scale for each core, and these processes are expected to take some time.
An associate member of the ANU team, Tony Rathburn from Indiana State University, will be returning to the United States with quite a bit of sediment collected from the multicores. This material provides information from the very top layers of the sea-floor, and typically contains foraminifera - unicellular organisms usually less than one millimeter in size.
Tony has sectioned the multicore samples into ½ cm slices, and then will mix the material with a chemical dye, rose Bengal, which stains living organisms pink. The stain will reveal the foraminifera - one of the most abundant organisms in the deep sea, the largest ecosystem on the planet. They are used extensively to assess palaeoceanographic and palaeoclimatologic change.
The multicore provides samples for last few hundred years, and material from the multicores will be studied for pine and vine pollen which will give information about the arrival of Europeans to Australia. They will also be tested for charcoal, as the Europeans systematically burned the landscape in the early white settler period. If charcoal is detected, further study will be conducted on the longer cores which will provide more detailed information.
Sabine Schmidt from France participated in the first leg of the AUSCAN voyage from Fremantle to Hobart. Sabine is a specialist whose particular area of research is Proactiniun - the study of accumulation rates of material in the seafloor. Samples will be transported to France for this aspect of the research, and Sabine will report back to Patrick De Deckker with her findings.
Lachie McLeay from SARDI will be returning to Adelaide with a lot of biological material from the canyons region. The conductivity, temperature and depth (CTD) data logger returned a lot of valuable information that will be used to further understand this unique area. So far, seven CTD profiles have been collected.
The CTD showed some areas which recorded very high readings of chlorophyll a (a variety of zooplankton) which relates to the presence of abundant algae. Algae are very important, as they form a principal food source for copepods and other organisms which are in turn are fed on by fish. The algal readings provide a good measurement of the organic productivity in the water column.
The team has also collected many sub-samples of water from the CTD for analysis of stable isotopes of carbon and oxygen. These particular elements do not decay over time, so provide a very useful record of hydrological phenomena (NELLI - I had “past events” - hydrological phenomena is Patrick’s suggestion). Water samples were taken to test for various trace metals. These results will help interpret analysis to be done on foraminifera from the cores. Hopefully the past sea-surface temperatures will be obtained from these analyses.
The benthic sled returned far less material than was originally anticipated. The material that was gathered will be sent to the SARDI laboratories where it will be distributed among experts in the Victoria and South Australian Museums for identification. SARDI will be responsible for the curation of the samples.
The plankton tows brought back a lot of material for Lachie McLeay. He is particularly interested in finding out about fish eggs and larvae in the region, especially where pilchards and blue mackerel might spawn. Closer research in the SARDI labs will reveal more, although initial testing has shown that many of the samples contain fish larvae.
Patrick De Deckker also has some plankton samples to look at, and in particular microscopic organisms with calcareous shells. “We want to find out more about what&rlquo;s in the water column,” he said. “Hopefully we may also compare our research with Baudin’s expedition two hundred years ago. Baudin’s team of researchers actually described some of the larger plankton, and hopefully we collected similar species during our trip in February and March. It will be a very interesting exercise, spanning two hundred years between collections,” he said.
The Marion Dufresne
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