Gone fishing...

On the offchance(!) that you aren't currently following the official Porcupine Abyssal Plain (PAP) Observatory blog, I thought I'd leave you a wee link to the post I wrote for them at the weekend about our trawling work. Enjoy!

https://papobservatory.wordpress.com/2015/07/06/gone-fishing/

Bringing the nets on board

The armoured grenadier, Coryphaenoides armatus, caught from 4850 m down!

Some of the other animals from the trawl catches. Left: Brittle stars (Ophiuroidea); Middle top: A sea cucumber (Holothuroidea); Middle: an Abyssal Grenadier (Coryphaenoides profundicolus); Middle bottom: an isopod; Right: A sea spider (Pycnogonidae)

Work, work, work (and sea monsters)

It's been a hectic two weeks.

Busy busy busy.

After the weather finally decided to stop chasing us around, we got ourselves over to our study site at the Porcupine Abyssal Plain to start what has probably been the most diverse range of deep-sea work I've encountered on a cruise! We've deployed and recovered environmental moorings, autonomous gliders, and a time-lapse camera ("Bathysnap") that's been photographing the seabed for the last 12 months; we've sliced mud, trapped amphipods and sampled a LOT of water!

Trawling in the Abyss

But the work that I came out here for was the trawling, and despite a couple of minor issues with the net along the way, we managed to catch ourselves a decent selection of fish which will help massively with confirming the species identifications of the fish I'm seeing in my photographs from the region. It's also a bit more data to add to our long-term dataset from the PAP which has been being added to gradually over the last 20 years and is one of only two such datasets to exist in the world, so all of this is pretty valuable.

The benthic fishes include the grenadiers (top four images) and eels (bottom image).

My primary interest is in the benthic fish (the ones that live on or close to the seafloor), like the ones in the image above. However, from a purely photographic point of view it's the pelagic or mid-water species that have been holding my attention over the past few days, because they are brilliantly monstrous little things! Here's a selection (most backgrounds have been photoshopped out and replaced with black):

Female Anglerfish

Female angler fish (head detail).

Gulper Eel (head detail)

Hatchetfish

As usual though, we unfortunately also collected a lot of litter in our catches. It's not surprising - this far offshore there are few regulations regarding the disposal of waste at sea (it's legal to dump most things once you reach international waters), but it's still a shame to think that even out here in an environment that is so distant from us, we're still disturbing and impacting it.

The litter brought up in our first trawl.

A coke can in the net.

 

 

I'm on a boat...

After a rather hectic weekend of data processing and frantic presentation-writing in time for a meeting yesterday, it's now time to pack up my rigger boots again and head to Southampton for another two weeks at sea for what is likely to be my very last cruise as part of my PhD.

Mud and muddy animals! Yeah! 

This time, we're heading back out to the Porcupine Abyssal Plain to learn how to trawl for sample in deep-water! I've done a similar trip before, but the guys who knew all the details of how to work the gear and get it properly set up are starting to leave or retire now, so there's a bunch of us heading offshore to gather as much knowledge as we can (and hopefully catch some interesting things while we're out there too!).

An abyssal grenadier almost 5000m down

As well as a lot of mud-sampling (it just wouldn't be a trip to the abyss without it!), we'll be conducting at least two seabed trawls and hoping to collect another batch of samples to add to the long-term dataset which has been being collected at the PAP site since the early 1980s to track temporal changes in abyssal animals over the course of several decades to improve our understanding of the fragility of those systems. As always, I'll be on the lookout for fish specimens to bring back with me, and will of course keep you posted on our progress as we go. Keep your fingers crossed for us getting good weather!

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! 

Compressing Confectionery at 5000m

Because most of the research I do is largely based on survey work with a dash of theoretical modelling, I don’t get to spend a lot of time working in the lab or designing experiments. However, this time I came to sea armed with a plan!

Mmmmm.... Sciencey!

As you may remember from previous cruises, people typically spend a lot of their downtime drawing designs on polystyrene cups, sending them to the seabed and letting the high pressure of the seawater crush them into miniatures. After making plenty of my own cups, the novelty began to wear off a bit and I started wondering what would happen to other things if you sent them into the abyss. In particular, I wondered what would happen to air-filled chocolates.

So, before I joined the ship I bought myself a bag of fun-size sweets containing Maltesers, Milky Way Stars, Milky Ways, Mars bars  and Starburst (or Opal Fruits if you’re still determined to remain old skool about it). With the exception of the starburst, all of them contain air-filled spaces to a greater or lesser extent, and although I didn’t formally measure the volume of air in each type, I would estimate that the maltesers have the most air with starburst having the least. I would have also liked to have sent down Aeros and Wispas to see what happens to them, but my local supermarket has a crap selection and this was all they had in the mini-sizes. Now, on to the science part!

Hypotheses

• The high pressure of the abyss (approximate 480 atmospheres) will crush the Maltesers and Milky Way Stars (being relatively brittle) completely. (Null hypothesis: Maltesers and Milky Way Stars will not crushed by the pressure.)
• The high pressure of the abyss will cause the Milky Ways and Mars Bars to shrink by reducing the volume of air in the nougat. (Null hypothesis: Size will remain the same.)

I didn’t really expect anything to happen to the starburst since there are no gas-filled spaces in them, but it seemed a shame to leave them out so I chucked them in as well. For science!

Study Design

Deploying the sock

Using fun-sized packets of sweets was a handy way of getting a reasonable number of replicates without wasting large quantities of chocolate to do it (which is virtually a cardinal sin when you’re at sea for a long time!). The packets were divided into experimental and control groups as shown in table 1. The experimental packets were wrapped in a plastic bag and placed into our handy sock* which was then cable-tied onto the frame of the megacorer.  The control groups were placed in a walk-in fridge set to 4°C (the temperature of abyssal seawater).

Figure 1: The test chocolates (below) and controls (above)

Table 1: Numbers of each type of sweet used in the experiment

Confection Type	No. Experimental Packets	No. Control Packets
Maltesers	2	1
Milky Way	3	1
Mars Bars	3	1
Milky Way Stars	3	1
Starburst	2	1

The megacorer was then deployed and sent down to approximately 4800m on the Porcupine Abyssal Plain before being recovered. The total trip took around 5 hours from leaving the deck to coming back on board. Once the sweets were back on the ship, the packets were opened, photographed and tasted by a (semi-) willing panel of curious masters students. 

Data Analysis

The students were delighted at the prospect of eating salty, wet chocolate.

The data analysis comprised two parts: qualitative observations and taste-tests of the experimental sweets compared to the control groups and comparative measurements of the lengths of each of the sweets. Because there is only one Milky Way or Mars Bar per packet, the lengths of these were recorded both before and after the experiment to compare the change in length. The Maltesers, Milky Way Stars and Starburst could not be effectively measured prior to the experiment since that would have required opening the packets, but since there are several individual sweets per packet that was not considered a problem.

The measurements of Mars bars and Milky Ways were made using calipers (without opening the packet), and all other measures were taken from the photographs using photoshop.

Results

General Observations

Although none of the packets had visible holes in them, seawater did manage to get into all the experimental sweets. Aside from making the taste tests more salty that we generally like, it also makes it hard to separate the effects of melting vs. pressure.

Mars Bar

Figure A: Mean lengths of the control vs. experimental Mars Bars. Error bars show one standard deviation, p > 0.05.

Figure B: An experimental Mars Bar (below) after the experiment showing no visible damage compared to the control bar (above).

The Mars bars showed no significant change in length as a result of their journey to the abyss (figure A; paired t-test: p > 0.05) and displayed virtually no signs of crushing damage at all (figure B) and the consensus on taste agreed that they tasted pretty much exactly the same as the control bar.

Milky Way

Figure C: The lengths of control and experimental Milky Ways before and after the experiment. Error bars show one standard deviation, p > 0.05.

Figure D: Milky Ways appeared to sustain more damage from the pressure than the Mars Bars.

Just like the Mars bars, the Milky Ways showed no obvious change in length after the experiment (figure C), but there were more obvious signs of having been crushed by the pressure (figure D). The taste panel agreed that the experimental Milky Ways were 'wet and disgusting'.

Maltesers

Figure E: Control Maltesers (left) compared to an experimental set (right).

As expected, the journey to the abyss had the most dramatic effects on the Maltesers which were so crushed from the trip that the experimental ones couldn't be measured (figure E). Strangely enough, these were popular with the tasting team who agreed that despite the fact that they were wet and rather salty, they were actually quite pleasant in a strange, chewy way. 

Milky Way Stars

Figure F: Experimental (left) compared to control (right) Milky Way Stars. Funnily enough, no-one was willing to try eating the experimental ones.

Figure G: Mean lengths of Milky Way Stars from each packet. Error bars show one standard deviation, p < 0.05. 

These were badly affected by water leakage and resembled a weird chocolatey soup (figure F). One of the experimental packets contained chocolates that were significantly smaller than the control (figure G; GLM: p < 0.05), but the other experimental groups showed no difference. Not surprisingly, we drew the line at tasting these and so we'll never know if they were still edible!

Starburst

Figure H: Mean width of control (red) and experimental starburst. Error bars show one standard deviation, p < 0.05.

Figure H: Experimental (left) compared to control (right) starbursts.

Figure I: An opened starburst showing the extent to which they had dissolved. 

Finally, we have the starburst. These were also badly affected by water leakage which turned them into a strange soup. Measurements taken on the wrapped sweets showed that the experimental groups were significantly wider than the control (figure H; GLM: p < 0.05), but this is likely due to the fact that they were pretty well liquefied by the time we got them (figures I & J). As with the Milky Way Stars, no-one was willing to try eating these so what salty, wet, melted Starbursts actually taste like will sadly remain a mystery.

Conclusions

It's pretty clear from this short study that the biggest issue with sending Mars funsize sweets into the abyss is non-waterproof packaging, which was generally considered a bad thing in terms of the appeal and taste of everything except the Mars Bars which seemed to be entirely unaltered by the whole affair. The effects of pressure weren't particularly exciting on anything except the Maltesers which seem to have been completely crushed by their descent to 4800m. 

Also, although students will eat almost anything, it seems that salty, melted chocolate soup is a step too far!

Thanks

Thanks to Claire, Alice, Tish and John for daring to taste these!

---

* Socks make useful impromptu containers because: a) SOMEONE always has an old sock they don’t mind sacrificing to the cause and b) it’s relatively easy to shove cable ties through wool.

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!

To the Abyss!

The tug boat maneuvering us out of port and away from NOC

Leaving Southampton behind us (click to enlarge)

And we're off! After a relatively calm day yesterday to arrive and get acquainted with our new living arrangements aboard ship, we finally left Southampton harbour at lunchtime today, heading out on our way to the abyss! So far we've not really had much to do aside from going through the normal start-of-cruise safety and science briefings, and getting to know the other scientists and the ship so it's been quite a relaxed couple of days (which is a nice break after the chaos of preparing for the cruise!).

We have old skool life jackets!

Inside the life raft, listening to why abandoning ship would be all kinds of horrendous.

We've got a long way to go to get to our study site in the Porcupine Abyssal Plain (PAP), which means we'll not be arriving until first thing on Sunday, with a stop-off en route on Saturday to collect some 'shallow' mud and water samples (from only 1000m!) for one of the other PhD students. Saying that, there's plenty of preparatory work to be done to make sure all our equipment and computers are working properly and that we're ready to cope with the deluge of data we're expecting to get from the AUV on a daily basis. All being well, I'll have amassed an absolutely enormous collection of photographs by the time we come home (current estimates suggest we'll be getting 40,000 photos per day from each of the two cameras), and will have photographically and acoustically mapped an area of seabed of approximately 50km2, making this the largest and most detailed attempt to map a deep-sea area ever conducted! Hopefully with all those photographs I'll get to see plenty of fish!

Southampton harbour (click to enlarge).

In slightly different news, I've also been asked to keep the official NOC blog up to date as we go through the cruise, so if reading one blog by me isn't enough, you can pop over to http://picturingthedeep.blogspot.co.uk/ and read that one too! Though in fairness, the NOC one will be written by lots of different people, so you'll at least get plenty of variety!

Heading back to sea!

I still can't quite believe I'm getting to spend so much time on research cruises this year! It's all very exciting! After the success of the Changing Oceans 2012 expedition which I was involved with last month, I've managed to grab a brief two weeks on shore before heading off tomorrow to join the RRS Discovery (the 50 year-old one, not the new one!) in Southampton to take part in the AESA cruise at the Porcupine Abyssal Plain (NE Atlantic). To give it its full title, the cruise is called:

Autonomous Ecological Surveying of the Abyss:

Understanding Mesoscale Spatial Heterogeneity

at the Porcupine Abyssal Plain

Which sounds pretty damn cool, doesn't it?

Essentially the aims of this cruise build on work we conducted on the RRS James Cook last August which aimed to collect preliminary data about the distributions of megafaunal animals across the abyssal seabed using an autonomous underwater vehicle (AUV). Unlike an ROV (a remotely-operated vehicle), which is constantly linked to the research ship via a tether cable and controlled directly by operators on-board, AUVs are pre-programmed with a route and details of what instruments to use and when, and then dropped into the sea where they will automatically follow their programming and then return to the surface when they're done. The lack of a tether system means that not only is the base ship able to continue working with other gears while the AUV is in the water, but that AUVs can access areas that are inaccessible to ROVs (e.g. under ice).

Image taken from the NOC website: http://www.noc.soton.ac.uk/aui/autosub.htm

The plan for the AESA cruise is therefore to send the AUV (we're using AUTOSUB) down to the abyss and send it off to conduct photographic surveys of the seafloor to assess how different animals are distributed across the seabed and how they respond to changes in the seafloor habitats (e.g. surrounding and on top of abyssal mud mounds) over a relatively fine scale. As usual, I'll be studying the fish that we see on the forward-facing camera, while others will be studying the invertebrate fauna using a downward-facing camera. Continuous surveying of physical environmental parameters will also be done at the same time. And while the AUV is busily collecting all its data, we can continue to work on collecting, processing and storing... you guessed it! Mud! I can't wait!

Deep-sea mud. Glorious, glorious, mud!

Since the RRS Discovery is the older sister-ship to the RRS James Cook, I'm expecting that we should have some (albeit limited) internet access while we're away, so I will hopefully be able to keep you updated on our progress and any other cool things we see as we go through the cruise. Also, since my research typically involves video & photographic analysis rather than lab work, I've made up a little side project of my own to run alongside the serious science! ... But you'll have to wait and see to find out what it is!