Research

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Research

Museum staff, researchers, students and community members use the state collections to conduct research - from life at the bottom of the ocean to the history of our state and its people.

Cork Colosseum x-ray

Author
by Kate C
Publish date
17 April 2014
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An x-ray machine usually employed for mammography examined an unconventional patient earlier this year: a model of the Colosseum made from cork around 1800. Thanks to generous assistance from Lake Imaging in North Melbourne, object conservator Sarah Babister now has a view inside one of our most curious objects.

Four people discuss photograph Conservators Sarah and Dani show radiographers Jeff and Ghazia a photo of the Colosseum model.
Source: Museum Victoria

cork Colosseum model The facade of the Colosseum model. (HT 24386)
Source: Museum Victoria
 

Radiographer Ghazia adjusted the settings of the mammography machine to accomodate this unusual material—cork is much less dense than human tissue—and produced wonderfully clear and informative images of several pieces of the Colosseum.

Woman with x-ray machine Ghazia placing a piece of the Colosseum on the mammography machine.
Source: Museum Victoria

Woman with computer Ghazia adjusting the levels of the x-ray to best show the hidden structure within the cork Colosseum.
Source: Museum Victoria
 

We think that our Colosseum was built by English model-maker Richard Du Bourg (or Dubourg), but in the absence of a signature, Sarah is looking for characteristic materials and construction techniques that could confirm its maker. Further research by historian (and the museum’s Head of Humanities) Richard Gillespie and genealogist Neil Gill is fleshing out the intriguing story of Du Bourg and his models; Richard recently visited similar objects in overseas collections for comparison. Sarah and Richard will present a talk about the model and its story next month as a part of the History, Cultures and Collections seminar series.

From 1775 to 1819, Du Bourg’s models of classical ruins were the height of fashion and his a well-known London exhibition. “He’s a fascinating character,” says Sarah. Notoriously, his working model of Vesuvius destroyed an entire exhibition when its eruption set fire to all the other models on display. “He lived until he was in his early 90s and even though he’d been very famous he was living in poverty.”

Sarah explains that cork models “were really popular at a certain time and were kept as tools to teach students. Then they fell out of fashion and a lot of them were disposed of.” This may explain Du Bourg’s impoverished old age, and is the reason why the museum has this model at all – in 1929 it was sent from the Science Museum in London to the Industrial and Technological Museum in Melbourne.

cork Colosseum detail Sarah holding a large piece of the Colosseum model.
Source: Museum Victoria
 

The model is over a metre wide and in poor condition. The base it sits on is cracked and the gesso applied to the perimeter is flaking, and several sections of wall have broken off. These broken sections are a mixed blessing, since without them there could be no x-rays, which reveal the lead pencil marking lines, and pins and nails used to hold the pieces of cork together. This information may help confirm whether Du Bourg made the model, but will also help Sarah reattach the broken pieces.

X-ray image of a piece of the cork Colosseum X-ray image of a piece of the cork Colosseum. The metal pins, and decorative carvings covered in lead paint, appear white.
Image: Lake Imaging
Source: Museum Victoria
 

“Most of the pieces are there so the model would be virtually complete with the exception of a few small columns which might need to be replicated,” she says. “I’d love to put it back together so it can be viewed how it should be viewed because it’s such an amazing object. The level of detail in the carving is wonderful, and cork lends itself so well to representing that ruinous state.”

To learn what the x-rays revealed, come along to Richard and Sarah's free seminar on 14 May, titled For the Nobility, Gentry & Curious in General: Richard Du Bourg’s Classical Exhibition, 1775-1819.

Links:

Cork Colosseum model on Collections Online

Rings around an asteroid

Author
by Tanya
Publish date
31 March 2014
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In a surprise discovery, two rings have been found around the asteroid Chariklo, making it the first small Solar System body known to have rings.

Saturn is known for its magnificent rings and the other gas giants - Jupiter, Uranus and Neptune - have ring systems too, though not quite as impressive. Careful searches had not found any other ring systems within the Solar System and many astronomers were beginning to think that rings might only exist around large objects, until now.

Rings from Chariklo An artist's impression of the newly discovered rings around Chariklo.
Source: ESO/L. Calçada/Nick Risinger (skysurvey.org)
 

Chariklo is just 250km across and lies beyond Saturn, at a billion kilometres away. It is much too small and far away for the rings themselves to be seen, but amazing detail is now known about them. The rings are dense but narrow, just three and seven kilometres wide, and are separated by a clear gap of nine kilometres. If you were standing on the surface of Chariklo, the rings would appear as wide as our Full Moon and stretch from horizon to horizon.

The discovery was made possible because last June, Chariklo passed in front of an obscure star (UCAC4 248-108672). Not only did Chariklo block the star's light for 5 seconds, but two tiny dips in the starlight were seen, just before and after Chariklo moved by. This video from the European Southern Observatory (ESO) shows faint dimming caused by the rings, just before and after Chariklo blocks the star completely.

 

This event, known as an occultation, could only be seen from South America and an observing campaign was coordinated across seven observatories, including two telescopes operated by the ESO at La Silla, Chile. Having observations from all seven observatories, ruled out other possible explanations, except for a ring system.

What I really love is the data from the new high-resolution camera on ESO's 1.54m Danish telescope. (Anyone who has been to my Discover the Night Sky series knows that I am particularly fond of beautiful graphs!) This new camera was developed to search for exoplanets and can take up to 40 images per second. It was actually able to see the gap between the two rings – now that's beautiful science!

Chariklo Data The data captured by ESO's 1.54m Danish telescope, showing Chariklo blocking out the light of the star (the main dip). On either side are two small, double dips, as the rings also passed in front of the star.
Image: F. Braga-Ribas et al.
Source: Reprinted by permission from Macmillan Publishers Ltd: Nature (March, 2014)
 

The Planetarium's astronomer, Dr Tanya Hill, was recently appointed the Australian representative of the European Southern Observatory's Science Outreach Network.

Links:

Smoky mouse update

Author
by Phoebe Burns
Publish date
25 February 2014
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Phoebe is a University of Melbourne Masters student supervised by Dr. Kevin Rowe at MV. She is studying post-fire distribution and ecology of the Smoky Mouse in the Grampians National Park.

In September 2013, I moved to the Grampians, pitched a tent and set out to see how the endangered Smoky Mouse, Pseudomys fumeus, was faring in the aftermath of the February 2013 Victoria Valley fire. After three soot-covered months, I’m back in Melbourne enjoying modern comforts like showers and instant boiling water.

Grampians landscape Grampians landscape
Image: Phoebe Burns
Source: Museum Victoria
 

I began my surveys at the site where, prior to the fire, we found a healthy population of Smoky Mice in the November 2012 Museum Victoria Bioscan. By September regrowing bracken ferns and eucalypts added a splash of green to the blackened landscape. In spite of the devastation, I caught several healthy Smoky Mice including some of the same individuals we’d caught the previous November! The ecological significance of this discovery alone was cause to celebrate.

Adult Smoky Mouse Adult Smoky Mouse on a burnt log
Image: Phoebe Burns
Source: Museum Victoria
 

Between my first capture in September and my final trapping night in December, I surveyed 46 sites in and out of the burn scar across the Victoria Range in the Grampians. At six of those sites, all within the burn scar, I found Smoky Mice living in the rocky habitats. The mice in these populations were not just surviving, they were healthy and breeding. I caught adults weighing as much as 70 grams but I also found tiny juveniles newly emerged from the nest weighing only 12 grams.  

Juvenile Smoky Mouse Juvenile Smoky Mouse
Image: Phoebe Burns
Source: Museum Victoria
 

While I was looking to find Smoky Mice, my trapping methods meant I also caught a number of other small mammal species (and a few reptiles). I was lucky enough to encounter Swamp Rats, Rattus lutreolus, Heath Mice, Pseudomys shortridgei, Agile Antechinus, Antechinus agilis, and Dusky Antechinus, Antechinus swainsonii. The highlights of my small mammal by-catch were two tiny Eastern Pygmy Possums, Cercatus nanus, that found their way into my traps.

Eastern Pygmy Possum Adult female Eastern Pygmy Possum
Image: Phoebe Burns
Source: Museum Victoria
 

The last three months were physically and mentally challenging, hiking up mountainsides in the rain and hail, being snowed on one day and sweating in the heat the next, but it was worth every unpredictable minute. I feel so privileged to explore the beautiful, rugged wilderness of the Grampians National Park and to have encountered so many remarkable species. The Parks Victoria staff provided a wealth of logistical and emotional support. It’s great to know that our parks are in such capable hands and that the Smoky Mice of the Victoria Range are thriving in spite of the fires.

Links:

MV Blog: Smoky Mice in the Grampians

Sea anemone feast

Author
by Michela Mitchell
Publish date
7 February 2014
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Michela is the first resident taxonomist of Actiniaria (sea anemones) in Australia. This title doesn't come with a ceremonial sash, but it should.

Photographed by Dr Julian Finn on a recent dive trip to Nelson Bay, New South Wales, this sea anemone is taking on a shrimp feast to rival that of an Aussie BBQ. 

Sea anemone A sea anemone, Phlyctenanthus australis, chowing down on a Hinge-back Shrimp, Rhynchocinetes serratus. There's also a photobombing chiton in the background.
Image: Julian Finn
Source: Museum Victoria
 

Little has been documented about the diets of sea anemones, particularly in Australia. These chance encounters and images help us understand these predominately sedentary animals (although, they can set a cracking pace if they so desire) and what role they play in the marine ecosystem. 

Sea anemones are opportunistic feeders that catch whatever food passes by. Prey is ensnared and then immobilised with specialised stinging cells (nematocysts) found in the tissue of sea anemones.

There are many different types of nematocysts and each has its own function; some are sticky for catching prey, some poisonous, others are used in self-defence. When feeding, the anemone extrudes its mouth and throat (actinopharynx) over the prey, sometimes completely enclosing it. The sea anemone then crushes and digests the food in the throat, which also acts as the gullet. Food waste is then ejected back out the mouth, which doubles as the anus.

Not all sea anemones are totally reliant on eating; some have a symbiosis with zooxanthellae (microscopic algae) that live in their tissues, and the sea anemone can use nutrients created by the photosynthesising algae.

Address to a haggis?

Author
by Meg
Publish date
25 January 2014
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As we rise on the morning of January 26th to celebrate our national day, Australia Day, on the opposite side of the globe another proud national celebration will also be getting underway – the Burns Night Supper in bonnie Scotland.

Robbie, or Rabbie, Burns (1759 – 1796) was a Scottish bard (poet) and one of the nation’s most celebrated figures, and each year Scots both at home and abroad commemorate his life and work on the evening of his birthday on January 25th.

Robert Burns Robert Burns
Image: Alexander Nasmyth (artist)
Source: Scottish National Portrait Gallery
 

Burns Night Suppers are usually organised and hosted by Burns Clubs, and in their most formal incarnations they have taken on a prescribed form – the evening begins with the piping in of the guests, who when seated then share in a reading of the Selkirk Grace, a prayer of thanks for the forthcoming meal. The prayer reads, in Scots:

"Some hae meat and cannae eat,
And some wad eat that want it,
But we hae meat and we can eat,
And sae the Lord be thankit."

Haggis at a Burns Supper Haggis at a Burns Supper
Image: Kim Traynor
Source: Kim Traynor
 

The piping then resumes to welcome the haggis which arrives in a procession accompanied by the chef, the piper and the reader nominated to address the haggis. Once settled on the table, the reader delivers the Address to the haggis, a poem composed by Burns in 1786 in honour of the dish. The address is followed by a toast to the haggis, and finally the “great chieftain o’ the pudding-race” is served alongside its traditional companions “neeps” and “tatties” (turnips and potatoes) with a dash of whisky sauce (often just neat whisky), and the feast begins.

Haggis, neeps and tatties Haggis, neeps and tatties
Image: Meg Lomax
Source: Meg Lomax
 

Other examples of Burns’ works are read throughout the evening, and the celebration traditionally draws to a close with a rousing rendition of Burns’ famous song Auld Lang Syne.

Appreciation for Burns’ words remains a strong feature of Scottish ex-patriot communities across the world and the Scottish community in Victoria is no exception – in January 2014, the Robert Burns Club of Melbourne will continue the tradition by hosting its 64th annual Burns Supper. And for those luck folk who identify as Scottish Australians, the haggis feast of the night before might be followed up with the (not too dissimilar) national dish of Australia the next day – the good old Aussie meat pie.

Alpine frogs and chytrid fungus

Author
by Kate C
Publish date
17 January 2014
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Frogs were an important focus for the Alps Bioscan survey in Victoria's Alpine National Park in November last year. The deadly amphibian chytrid fungus, Batrachochytrium dendrobatidis, thrives in cool environments, meaning high-altitude frog populations are particularly susceptible.

Dr Katie Smith, Collection Manager of Vertebrates, led the frog-hunting team at the Alps and explained why this fungus is so insidious. "It's a major contributor to global amphibian decline. Lots of frogs worldwide are affected," she said. "It penetrates their skin and leads to death in some species and individuals, while some are able to survive it and act as carriers."

View this video with a transcript

The museum's frog team searched for frogs in several sites in the Alps and collected skin swabs from every frog found. The swabs will be tested for the presence of chytrid (pronounced 'kit-trid') as part of ongoing monitoring by researchers from the Arthur Rylah Institute for Environmental Research. "We need to know what populations have it and whether this leads to changes in those populations, such as whether there's lower species diversity in areas where chytrid fungus is present."

The chytrid fungus has a free-living stage called a zoospore and a reproductive stage called a zoosporangium. Zoospores can live several weeks in the water until they find a host frog to infect. Once settled, the zoosporangia cause the frog's skin to thicken and slough away. There are a few hypotheses as to how the chytrid fungus kills frogs. One hypothesis proposes that a frog with a heavy chytrid infestation can't maintain its salt balance. Sodium and potassium levels, essential for normal muscle and nerve function, drop significantly and the frog dies from cardiac arrest.

froglet A froglet found during the Alps Bioscan. Froglet species seem to have some resistance to chytrid fungus, and may act as carriers between water bodies.
Image: David Paul
Source: Museum Victoria
 

Researchers believe that the fungus arrived in Australia in the 1970s, and is linked to the sudden decline (and in some cases, extinction,) of several local species, including the Southern Gastric Brooding Frog and the Southern Corroborree Frog. There are a few theories about how it got here, but the most likely culprit is the international trade in African Clawed Frogs for use in pregnancy tests. In the 1930s it was discovered that injecting one of these frogs with the urine of a pregnant woman caused the animal to produce eggs. Hundreds of thousands of frogs were brought into Australia from Africa for this purpose and probably, with them, the chytrid fungus. While the fungus was first identified in 1998, retrospective examination of historical specimens found the earliest known chytrid infestation on an animal collected in 1938. This African Clawed Frog specimen, held by the South African Museum, supports the theory of African origin.

Once loose in a new environment, chytrid fungus can spread rapidly. "It can be spread by frogs – anything that moves through those water bodies, even other animals that visit those areas and researchers themselves," explained Katie. "You might walk into one site, jump in the car and accidentally transfer it to a healthy population."

You can help prevent the spread of chytrid fungus in a couple of ways. Firstly, says Katie, "never move a frog, tadpoles or eggs that you find in one area to another area, because you don't know which populations may have the chytrid fungus." Frogs are protected in Australia which means that you cannot legally catch, remove or relocate them; the threat of chytrid fungus is another good reason to leave them where they are. Frogs often hitchhike from Queensland in bunches of bananas, so if you find a stowaway in your supermarket, follow the instructions of the Victorian Frog Group and never release the frog into the wild.

Katie continued, "secondly, if you're moving between water bodies, wash your shoes really well and anything else you put in water." The Alps Bioscan teams bleached and scrubbed shoes and equipment between each aquatic field site, and Katie's frog team wore fresh surgical gloves when handling each frog.

The results from the survey and chytrid tests will be available later this year once the researchers have completed their analysis.

Links:

Ché Weldon, Louis H. du Preez, Alex D. Hyatt, Reinhold Muller,and Rick Speare. Origin of the Amphibian Chytrid FungusEmerg Infect Dis. 2004 December; 10(12): 2100–2105.

David Hunter, Rod Pietsch, Nick Clemann, Michael Scroggie, Gregory Hollis and Gerry Marantelli. Prevalence of the Amphibian Chytrid Fungus (Batrachochytrium dendrobatidis) in Populations of Two Frog Species in the Australian Alps. 

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