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DISPLAYING POSTS BY: Mel (1)

Ice Ice Baby

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by Mel
Publish date
3 May 2012
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Mel helps manage MV's Marine Invertebrates collections. In her spare time she works with honorary associate Mark O’Loughlin and others to develop her specialist knowledge of holothuroids, or sea cucumbers.

Ice was what I saw from my porthole each morning as I’d wake yet again to the realisation... Woohoo! I’m in Antarctica!

What a wonderful realisation it was. For nearly two months this summer my home was the British ice-strengthened research vessel the RSS James Clark Ross, and I loved every minute of my freezing, rolling, ice-crunching scientific voyage. On board at the invitation of the British Antarctic Survey and with the support of Museum Victoria, I was part of the biological research team tasked with collecting marine benthinc invertebrates from the shelf and slopes of the Weddell Sea in Western Antarctica.

View from the top View from the top of the RSS James Clark Ross
Image: Mel Mackenzie
Source: Museum Victoria

My regular work in the museum's Marine Invertebrate Collections held me in good stead to assist the biological team with our daily work of collecting, sorting, identifying, preserving, and DNA-sampling specimens as we brought these bottom-dwelling 'beasties' up in nets and sleds from the ocean floor. Our aim was to assess the biodiversity and evolutionary history of the area, and my particular focus was on sea cucumbers (holothuroids) which I have studied for a number of years now under the mentorship of Museum Victoria honorary associate Mark O'Loughlin.

James Rudd (ship’s doctor) The biology team
Image: Mel Mackenzie
Source: British Antarctic Survey

Relatives of animals such as the sea star, many sea cucumbers actually look more like sausages with tentacles (which explains their name), and have developed a variety of different feeding and reproductive methods to adapt to environments worldwide. They are diverse in Antarctic waters with over 180 species (including many undescribed) recorded south of the Antarctic Convergence, and as such, they make a good group for evolutionary study. Often coming up squashed in trawls they can be tricky to identify, but the key lies in a variety of identifiers from tentacle shape and number, to tube-foot arrangement and the tiny little skeletal remnants known as 'ossicles' which can be viewed in dissolved tissue under a microscope.

Sea cucumbers and bivalves clinging to urchin spines. Sea cucumbers and bivalves clinging to urchin spines.
Image: Mel Mackenzie
Source: Museum Victoria

With my previous experience of Antarctic sea cucumbers limited to pickled museum specimens, I was very excited to finally see these animals in living colour! They were amazingly diverse, from the tiny Psolids which clung to sea-urchin spines, to my favourite football-shaped 'sea-pigs' which the ship crew were delighted to see. We even got some footage (from cameras lashed to one of our collecting sleds) of different species feeding and moving about on the sea floor.

Along with sea cucumbers we saw many other amazing critters, from nets crawling with sea spiders to beautiful glass sponges filled with brittle stars and deep-sea fish with 'lights' attached to their heads... and that was just from below the water! On top we saw breaching Minke whales, majestic Emperors and curious (and chatty) chin-strap penguins against the always gorgeous background of floating icebergs. Stopping in the sub-Antarctic British Base at Signey to help close up for winter, we even had the chance to see (while firmly holding our noses) the huge elephant seals which roll their way around the camp.

Emperor penguin (left), Elephant seals Emperor penguin (left), Elephant seals at the UK’s Signy base
Image: Mel Mackenzie
Source: Museum Victoria

Links:

Skeletons of sea cucumbers, MV Blog post, April 2011

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