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DISPLAYING POSTS TAGGED: marine biology (32)

Spawning sea anenomes

Author
by Michela Mitchell
Publish date
5 November 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.

The Field Naturalists Marine Research Group members Joan Hales and Janet Davies sent me this gorgeous photo of the Victorian sea anemone, Oulactis sp., spawning last week.

Spawing sea anemone Female Oulactis sp. spawning with tiny pink eggs on the oral disc.
Image: Joan Hales
Source: Joan Hales
 

Sea anemones are closely related to corals and so, like corals, they spawn under the right conditions and environmental cues, usually in spring and summer. This can be associated with cycles of the moon. This particular anemone reproduces by broadcast spawning; females and males release eggs and sperm into the water column, where the tides and currents brings spermatoza into contact with the eggs for fertilisation.

This method is not for all species of anemones, however. Some have cunningly evolved various methods of reproduction (sexual and asexual) so they can stick around as long as they need to. Some species can even change the way they reproduce: they can clone themselves, they can split in half (fission), or leave a small fragment of their pedal disc (laceration) behind and a whole new anemone can grow. They can even be male and female together (hermaphroditic). They leave nothing to chance ensuring their survival on Earth – so far 600 million years and counting!

Filming our underwater backyard

Author
by Kate C
Publish date
23 October 2014
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What do you know of the Vampire Squid? How about the Dragonfish, the Sea Mouse and the Fangtooth? These bizarre animals live kilometres – yes, kilometres – beneath the ocean’s surface. We’ve brought them up to sea level for you to meet at the exhibition Deep Oceans, which opens this weekend at Scienceworks.

Anglerfish exhibit Deep Oceans Anglerfish exhibit
Image: Australian Museum
Source: Australian Museum
 

This exhibition comes to us from the Australian Museum and we’ve added some local characters to the mix. Parks Victoria tells us that nearly half of Port Phillip is less than eight metres deep, and its greatest depth is only 24 metres. It’s just a puddle compared to the true deep oceans. This means we can see a huge diversity of our marine life just by heading out into the bay with a mask and snorkel.

 

Over the past months, Dr Julian Finn has filmed seals, fish, crabs and others in our local marine parks with a fish-eye lens. This footage will be projected inside the Underwater Backyard virtual aquarium dome, where you can stand right beside the bay’s residents without getting wet.

Deep Oceans is at Scienceworks 25 October 2014 to 12 April 2015.

Catalogue of cephalopods completed

Author
by Kate C
Publish date
4 June 2014
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Everyone loves a happy ending. And everyone loves octopuses. The recent completion of the third and final volume in the revised FAO Catalogue of Cephalopods of the World nails it on both fronts. 

Cephalopods of the World Volume 3 Cover of the new FAO Cephalopods of the World Volume 3.
Image: Emanuela D’Antoni
Source: Food and Agriculture Organization of the United Nations
 

This is a brilliant – and free – resource designed to assist people working in fisheries to identify the cephalopods that we humans are most aware of, namely the ones we've identified, that we eat, or can cause us harm. Volume 3: Octopods and Vampire Squids was co-authored by MV's Dr Mark Norman and Dr Julian Finn. They are also are two of the four series editors.

'Octopus’ berrima Spot the 'Octopus’ berrima in the sandy substrate! (The inverted commas signify that this species is provisionally placed in the genus Octopus.)
Image: Julian Finn
Source: Museum Victoria
 

Years of work and drawing from cephalopod researchers worldwide sees FAO Catalogue of Cephalopods of the World summarising descriptions of species for practical use by non-specialists. "We've distilled it down to diagnostic characters that will allow people on research or fishing vessels to identify species," says Julian. "It's a review of all the taxonomic work that's out there, for people who don't have immediate access to the literature." The species descriptions focus on traits that are easily measured, which is no mean feat for animals famous for changing their shape and form at will. Says Julian, "everything is based on characters that survive preservation and are consistent across members of a species, such as numbers of suckers, presence or absence of structures, and relative lengths of body components."

Julian and Mark also note that this project would not have been possible without significant financial and moral support from the Australian Biological Resources Study and the Hermon Slade Foundation. This allowed them to do the work on octopus taxonomy that was required for this new edition of the Catalogue. 

Argonauta argo The beautiful female Argonaut, or Argonauta argo.
Image: Julian Finn
Source: Museum Victoria
 

So, if you have an interest in, as Ze Frank calls them, 'the floppy floppy spiders of the sea', head to FAO and download a free copy of FAO Catalogue of Cephalopods of the World Volume 3 (PDF, 25.77Mb). And in case you need a reminder about why you love octopuses, here's a video showing how they can open jars from the inside (while we humans sometimes struggle to open them from the outside).

 

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.

Sayonara, Southern Surveyor

Author
by Kate C
Publish date
12 August 2013
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After decades of sampling the oceans in the name of science, CSIRO's research vessel Southern Surveyor made its final voyage in July this year. Its last trip was featured on ABC's Catalyst earlier this month.

The Museum Victoria collections have many reasons to thank RV Southern Surveyor, as several of our researchers have collected thousands of deep-sea octopuses, brittle stars, feather stars, shrimps, crabs and more while on board. In 2011, Dr Anna McCallum completed her PhD based upon data from two surveys of the WA continental margin, for which she left her cosy desk at Melbourne Museum and went to sea in what she describes as more of a "floating factory" than a cruise ship.

Anna McCallum on the bridge of RV Southern Surveyor Anna McCallum on the bridge of RV Southern Surveyor
Source: Museum Victoria
 

For over two weeks, the Southern Surveyor's crew hauled up animals that live between 100 and 1000 metres below the water's surface. They brought them into the ship's laboratory where Anna and other scientists worked in 12-hour shifts to sort, photograph and preserve the specimens. "Often there would be a backlog. We'd be working as hard as we could and they'd come in saying OK, here's the next load! The ship works 24 hours, non-stop, because once you're out there, you want to make use of all the time you've got." With long hours and frequent seasickness, it's hard work, but it's exciting; as Anna says, "most museum scientists will only look at deep-sea animals in jars, and this is one of the rare opportunities to see these animals when they're alive."

Crab, <em>Phylyra</em> sp. A tiny crab collected on a Southern Surveyor voyage, Phylyra sp, a probably new species that Anna affectionately calls 'muscle crab'.
Image: Karen Gowlett-Holmes
Source: CSIRO
 

Once back on land, identifying the specimens takes many months to years. Anna's speciality is Decapoda – the order of crustaceans that includes crayfish, crabs, lobsters, prawns and shrimp. 30 per cent of the almost 900 species of decapods collected during Anna's two surveys were new to science, while 140 were described but never before recorded from Australia waters. Research trips on the Southern Surveyor have dramatically increased our understanding of the deep-sea's astonishing biodiversity.

Crab <em>Leucosia haematostica</em> A specimen of the crab Leucosia haematostica found at 100 m. the first time it was recorded in Australia.
Image: Karen Gowlett-Holmes
Source: CSIRO
 

"Being out in the open ocean is different to anything you can experience in the bay," says Anna. "Once you get beyond the shelf, the swell is really big. But it's exciting and there's the camaraderie with your colleagues. Jo Browne was on a voyage with me and occasionally we found half an hour to lie in the sun up on deck and eat ice cream. It was just bliss, a small gap in two weeks of hard work."

Men processing marine samples in lab Two of the museum's marine biologists, Robin Wilson and Tim O'Hara, working in the lab of RV Southern Surveyor.
Source: Museum Victoria
 

So the museum salutes RV Southern Surveyor and eagerly awaits its replacement, the new RV Investigator. This vessel is currently under construction and will be able to travel further south than its predecessor, telling us even more about the life in the ocean.

Links:

CSIRO Marine National Facility RV Southern Surveyor

Science Reports no. 11:  Decapod Crustacea of the continental margin of southwestern and central Western Australia Gary C. B. Poore, Anna W. McCallum and Joanne Taylor (2008)

3D printing at SmartBar

Author
by Ely Wallis
Publish date
16 May 2013
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The theme of the most recent SmartBar at Melbourne Museum was 'retrofuturism'. A perfect theme to base a demonstration of technology that's definitely more future than retro – 3D printing.

During the evening we had two printers set up: the Museum's recently-purchased MakerBot Replicator2 and a printer brought along by our colleagues Bernard Meade and Ben Kreunen (from The University of Melbourne). Bernard and Ben also brought along a 3D scanner, and spent the evening scanning specimens from our Marine Invertebrates collection.

A crowd of people view 3D printers 3D printers and scanner demonstration with an enthusiastic and interested crowd at SmartBar, Melbourne Museum, April 2013.
Image: Ben Kreunen
Source: The University of Melbourne
 

We had an incredibly positive response with people very interested to see the new technology demonstrated. One reaction was surprise that the Museum is experimenting in this emerging field. “What are you going to use it for?” was a common question. The answer ranges from science (especially palaeontological) research, to rapid prototyping of exhibition components, to modelling. And the list will continue to grow. Other museums are also experimenting, and 3D printing maker spaces have been popping up at museum technology conferences for a couple of years now.

We also used the deadline of SmartBar to test out possible workflows, as we have also recently purchased a 3D scanner. With the scanner located in our Media Production department, our best expertise at handling 3D files located in our Design team, and the printer located in our Digital and Emerging Technology department, we wanted to see how well a new cross-department workflow might go.

3D printer in operation The MakerBot Replicator2 in action, printing an ammonite.
Image: Ely Wallis
Source: Museum Victoria
 

Our Sciences department supplied some collection specimens to scan, which we did more and less successfully. The best was an ammonite, and our scan of a trilobite was okay, though we want to try printing it end on to get better relief detail.

Less successful was a biscuit star which looked to have enough surface detail to scan well, but which ended up looking like a lump of dough. The lessons learned were that we should upgrade our scanning software, and that we need a lot more practice in how to fill in ends and merge multiple scans to get a complex 3D shape with no holes.

The least successful, but amusing, experiment was an attempt to scan quartz crystals. Lovely shapes but the lasers passed straight through or bounced off the clear crystals, providing a very pretty laser light show but no scan. Next time we’ll try powdering them to get a better matt surface.

White ammonite specimen next to black plastic one Real ammonite specimen from Museum Victoria’s palaeontology collection, next to the 3D printed model.
Image: Ben Healley
Source: Museum Victoria
 

All in all, it was a fun night, and a successful first attempt at our own scanning and printing. Congratulations to all who attended SmartBar and got to take home their own 3D printed ammonite. In case you’re interested, the original is a fossil Pleuroceras sp, which was found in Bavaria in Germany.

We have now uploaded the ammonite scan to Museum Victoria’s collection (of one!) in Thingiverse, a website for sharing 3D printable files and where you’ll find other museums also uploading scans. We’ll continue to add specimens and models there over time.

Happy printing!

(see also Amstrad on display at SmartBar)

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Updates on what's happening at Melbourne Museum, the Immigration Museum, Scienceworks, the Royal Exhibition Building, and beyond.

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