May 19, 2017

Sunset reflected on the RV Investigator at sea
Sunset relects on the CSIRO RV Investigator. Image: Asher Flatt

Blogging the abyss iconDay 5: Asher Flatt, onboard communicator (part 1)

Instead of going to bed on Wednesday night, I decided to stay up to catch the action of the first beam trawl, set to emerge from the depths at about 3 am. By 3 am the trawl was still half an hour away, by 3:30 am the trawl was still half an hour away. Finally, at about 4 am, I ventured onto the deck to set up a time-lapse of the action. Soon after, the first ship’s crew arrived, and 10 minutes later the net was above the water and being hauled on deck. Scientists came out and began efficiently sorting specimens into plastic tubs full of chilled salt water to be taken back to the lab for further identification and processing.

“It was a good haul with lots of diversity,” says Merrick Ekins of Queensland Museum. “There were thousands of brittle stars and seastars, a penis worm (Priapulida) and lots of purple people eaters (an affectionate term for a type of holothuroid, or sea cucumber) that made up the bulk of the catch. We also had one hundred of the same type of anemone, which, when fixed in ethanol, looked like a toilet roll.”

The other highlight, for the fish people, was a beautiful looking tripod fish with its tentacle-like protrusions for balancing on the seafloor.

Next to go down was the brenke sled, to gather sediment samples from the sea-floor. I wasn't there to witness it as I was fast asleep, but there was some surprise at how small the sample had been. Everyone thought something must have gone wrong, but then under the microscope a microcosm of life became apparent. Finally, the first beam trawl was sent down to depths of 4000 metres in the late morning, and did not emerge until about 7 pm.

The one time I managed to step outside today into the salty sea air was late afternoon. The sun was low in the sky and lit up the entire horizon. I took a few pictures and let the fresh sea air fill my lungs, as the light began to change from the brilliance of a burning yellow to warm orange, and finally a dull red on the horizon. A lone albatross swooped low above the waves, turning back and forth in arcs against the dying light.

Four scientists sorting samples on the RV Investigator
All hands in buckets! It's important to get the specimens quickly sorted, labelled and preserved. Image Asher Flatt
Kirrily Moore at the microscope
Kirrily Moore takes a closer look at a specimen hauled up from the deep. Image: Asher Flatt

Kirrily Moore, Tasmanian Museum and Art Gallery (part 2)

Our first beam trawl was hauled onto the deck at about 4:30 am on Thursday morning, and even on the small back deck camera we could tell there was biological material in the cod end (the small end at the tail of the net). It had come from the sea floor about 2700m below us.

The allocated eager scientists in full yellow wet weather gear and hard hats scooped, shovelled, picked and hauled specimens into many bins with pre-cooled sea water and ice, then these bins were brought into the lab. It was our first large catch from the seafloor and there was much excitement and exclamation.

We needed to sort the specimens into useful groups as quickly as we could. These creatures normally live in complete darkness, in frigid temperatures and under great pressure. Unfortunately most of them don’t survive the process of hauling them to the surface, but they are precious and we don’t want to waste anything, so we have to treat them gently but quickly to get them labelled, photographed and preserved.

Orange Kombi van
There are several steps to sorting the catch. You know it's a vehicle, you know it's a car, a Volkswagon and a Kombi, but you may not yet know what kind. Image: Shutterstock

We are often asked ‘how do you start?’ or ‘how do you know how to sort?’ and I often use this analogy. Imagine you have this Kombi photo in front of you. You know immediately it’s a vehicle. You just know, you’ve seen enough things with metal bodies and wheels to know it’s a vehicle. It’s not a fridge or a tree or a rock or anything else. That may be all you know, so you write it a label and call it 'Vehicle 1'.

But you might actually know more than that: you might know that cars have four wheels, (not two like a motorbike), so you could call it ‘Car 1’, thereby taking an extra step. But you might know even more: you know the sign on the front means it was made by Volkswagen, so you can write ‘Volkswagen 1’ on the label. Or you might know it’s a Kombi van so, you guessed, it ‘Kombi van 1’ on the label.

But just when you think you’ve got it, the next level to go to might be a much tricker question such as: is it a camper or a people mover? That’s impossible to tell from this photo. You might need more time, or a microscope to see inside, or an expert on Kombi campers. So, for the moment you’ve gone as far as you can to sort this ‘thing’ into a useful group.

A tray of unsorted deep-sea catch
A sample of invertebrates from the deep, pre-sorting. Time to apply the 'Kombi' technique! Image: Kirrily Moore

Sorting out what is in a tray from a trawl on the lab bench is a little like that. You use a combination of your experience and knowledge, and ask questions of those around you to identify it as far as practical. It can be a race to get everything sorted before the next trawl is due, so sorting to simple groups might be all we can do. Once the trawl is all sorted and preserved, each of the specialists on board can take their own group and try to identify the specimens to species level.

And don’t forget . . . obvious things such as what colour it is, or whether it has roof racks, doesn’t change the fact it’s a Kombi. It still has to be grouped with the other Kombis. And don’t forget the label!!!

Voyage date: 
Friday, May 19, 2017