A tale of half a million photographs

Well, this week has been busy! After a couple of issues with one of the batteries, the AUV team managed to get Autosub working perfectly again and we've been conducting photographic missions to the seafloor over the last five days, covering a survey track approximately 150km long and taking over 500,000 photographs in the process! It's the biggest AUV survey of an abyssal  region conducted to date (to the best of my knowledge) which is very cool and I'm hoping it will allow me to examine the distribution patterns of fish on the seafloor.

Autosub6000 being launched!
(I love that they've had to write 'harmless scientific instrument' on it in case it's mistaken for a giant yellow torpedo!

Deep-sea fish (particularly abyssal ones) are pretty difficult to study, partly because as the depth increases there's less and less food available which means fewer and fewer fish are able to survive. So, by the time you reach the abyssal plains at 4000-6000m, there are relatively few individuals around to find. One way around this problem is to use baited camera systems to lure the fish into your photographs, and it is an extremely efficient way of assessing the abundance and diversity of scavenging species in an ecosystem. However, scavenging species only account for around 25% of the  total fish diversity in the deep waters of the north-east Atlantic, so we need to use other techniques to identify the other 75%. A potential solution is to use unbaited cameras (such as Bathysnap), set to take images every few hours over several months then record which species pass by the camera in that time. Alternatively, we could catch specimens using trawl surveys to cover a larger area (which has the additional benefit that we can get definitive identifications for the species we catch), but we can't tell exactly whereabouts each fish was captured along the trawl's path.


However, none of these methods are really suitable for examining what the distribution patterns of fish are on the seafloor (i.e. do they cluster together or are they spread evenly over the seabed?) or how they respond to variations in habitat (e.g. how they react to the presence of hills or hard substrate), which are fairly fundamental questions to consider in understanding the ecology of any species. This is where Autosub comes into the picture. 

The forward-looking camera & flash on Autosub which  I use to look for fish.

As an AUV (Autonomous Underwater Vehicle), Autosub can be programmed to dive to the seafloor, follow a survey route while operating any on-board equipment (like cameras or sonar systems) and then return to the surface and the research ship without requiring any human intervention during its mission. Not only does this free the ship to conduct other work while the Autosub is getting on with its surveys, but it can also be programmed to conduct extremely long or complex surveys which may not be feasible using other methods. For our work, Autosub was set to conduct photographic transects roughly 35km - 90km in length, taking photographs every 0.86 seconds at a speed of around 1m per second. In case your mental arithmetic is a bit creaky, that's approximately 4200 photographs per hour! 



EDIT: Hooray! I've had the OK to post a few images, so here are a few of the better ones. They're cropped from a 5MP camera so they're not amazing quality, but they do the job!

Bathysaurus sp. (lizardfish) is an ambush predator with rather a lot  of teeth. They're not really orange, but the camera has a funny colour balance going on that I've not fixed yet.

A (not-colour-corrected) grenadier from yesterday's mission.

And another little grenadier from the first mission we did.

Anyway, after a rather full-on five days or so of AUV operations and between the two stills cameras mounted on Autosub, we've amassed well over 550,000 images and covered around 150km of abyssal seabed! A preliminary look through the photos is showing a decent number of fish as well which is brilliant news and means I'm going home with a really nice set of (pretty damn exciting) data! All of this is exceptionally cool, but sadly combines with the 100 hours of ROV footage from last month's cruise to sound the final death knell for my social life. Well, that and the prospect of several weeks on an Angolan oil rig at the end of the year, but that's still to be confirmed...

Examples of the rubbish we trawled up from the Porcupine Abyssal Plain during last year's cruise.

One thing that takes the shine off all this cool and exciting research though is that despite the fact that we're conducting surveys in 5000m of seawater in an area which isn't commercially targeted for anything (no fishing, mining, oil drilling etc.), we're still seeing litter everywhere, from planks of wood and scraps of metal to canvas bags to old books and old drinks cans and bottles. Last year when we were out here we trawled up boots, bottles and twice as much spent fuel (clinker) as animals by weight. It sucks. You'd think that maybe somewhere as remote as the ocean abysses might just be far enough away from us that they'd still be relatively pristine, but it's certainly not the case out here.


Finally, Jen Durden and I have written up a blog for the NOC's 'Picturing the Deep' blog which will hopefully go up online tomorrow (Tuesday at the latest I'd expect) so you can see some of it there at least in the meantime! 

The internet's back on! Time for a blog...

And so, after 4 days of travelling, we finally made it to our sampling stations in the Porcupine Abyssal Plain first thing on Sunday morning ready and excited to start working! ...At least the morning shift were up and ready to go - my afternoon (1500-0300) shift was a little slower to get out of bed, most of us just managing to get ourselves up in time to eat lunch! Still, I can't complain; doing the backshift is DEFINITELY the better option compared to having to get out of bed at 3am every day (I don't do mornings). 

It is quite interesting seeing how different people deal with the shifts though. Most people on board I think would prefer to work the 1500-0300 shift if they had the choice, but some definitely deal it better than others. For me, if I had to get up for 3am I would still wake up feeling like crap no matter when I went to bed, whereas working the backshift until 0300 is absolutely no problem and only took a day or two to get used to. It's also helping the productivity (well, that and the extremely intermittent internet connection means I can't get too distracted too easily!), which always helps ease the PhD Fear back a little bit!

Mud + Science = Fun times for all.

Anyway, aside from settling into our shifts and getting to know everyone else on the ship, we've been getting stuck into a lot of megacoring work, which basically involves sending a corer to the seabed armed with 8-10 plastic tubes, which will be forced into the seabed then mechanically sealed up and hauled all the way back up ready to be measured, cut into slices, preserved and stored. All in all, the whole cycle takes around 7 hours (5 hours to send the gear down and back up and about 2 hours to process) so there's plenty of time to escape off to do some work or watch a film in between cores (or bizarrely, learn how to play cribbage), which is nice because it's not the most exciting work! It's one of those team-effort type jobs though so it's a pretty good laugh at least.

Autosub on the back deck. 

Autosub (our AUV or 'Autonomous Underwater Vehicle') is still being prepared for it's first launch later this afternoon (Wednesday) so keep your fingers crossed that it all goes well! The plan for the next few days is to send it down to take a few test photographs on the seabed so we can make sure it's all working the way it's meant to, and then it will rise up to about 100m off the sea floor and conduct the first part of an acoustic mapping survey which will take about 6 days to complete. So there won't be any fishy photos to look at for a while yet I'm afraid!

A little mystery tern floating by on its own private polystyrene island. Click to enlarge.

In wildlife news, there hasn't been much in the way of bird life out here except for this little mystery tern which floated past the ship yesterday on a little polystyrene island. As usual, I've got very little idea what this is, but it doesn't look like any of the British species I've seen before. Anyone out there got any ideas?

Maybe a fin whale? A group of about 5-6 whales passed our ship yesterday but no-one could tell what species they were.

We also saw a lot of whales yesterday too, which was very exciting! They were pretty far away, but they were pretty big (one was probably >15m, though I'm horrible at estimates. Definitely bigger than a minke though) and we think they might have been fin whales. One day I'll buy an ID guide and be able to say for sure what all these things are that we find out here!