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25 April: Deeper & deeper (Scotia Arc Expedition 2013)

By: Dr Nerida Wilson, Category: Science, Date: 29 Apr 2013

We are now exploring the deeper parts of the Burdwood Bank.

25 April: Deeper & deeper (Scotia Arc Expedition 2013) #1

Greg Rouse © Australian Museum

Our usual trawls are about 100-200m deep, but now we are exploring at 350m and 800m. It takes a lot longer to put a trawl on the bottom when it's deep, so we have only been able to do a couple of these a day. It’s been worthwhile as we are seeing some different animals that do not occur in the very shallow areas.

My absolute favourite animal is this giant sea slug called Bathydoris. Most specimens I’ve seen have been about 5cm long (about 2 inches), but we came across this amazing huge specimen (over 20cm), and it was peach-pink coloured! Bill Baker, the resident chemist on board, will be looking at the chemicals this slug usually uses to keep predators from taking a bite.

We also launched an underwater video camera today, affectionately known as The Scud, since it looks like a crazy missile. It hasn’t been deployed for a while, so this was a bit of a test run. We took it to about 350m, and then looked at the imagery on board the ship. We need to change the direction of the lights a bit and add a diffuser. But most importantly there was a leak that needs to be fixed. The electronics technicians are currently working hard on solving these issues.

Best of all, the cooks made us some yummy ANZAC biscuits! It’s interesting to share history and culture with others on board. Ships are always a global village, and it’s a great opportunity to learn from each other.