: 2015

Deep beneath the ocean surface, where no sunlight can penetrate, there are areas so hot, volatile and toxic that it's hard to believe life can exist...but it does, and often in abundance. It is exactly this kind of hostile environment that one of our most recent natural history acquisitions came from, a spectacular marine snail called the 'scaly-foot gastropod', or for those of you who like Greek and Latin, Chrysomallon squamiferum Chen, Linse, Copley & Rogers, 2015 (fig. 1). It comes from depths of 2785m, living on the edge of hydrothermal vents and black smokers that reach temperatures of 300-400°C. This is certainly not your average snail...

Under armour and ready for battle

It was in 2000 that the first hydrothermal vent field was discovered in the Indian Ocean, known as Kairei field, and a year on that Woods Hole surveyed the area in the RV Knorr 162-13 and encountered this new species. It was immediately obvious that something unique had been discovered. The 'foot' of this snail, which is the fleshy soft part that snails move around on, displayed hundreds of hardened tags, almost like an armour. These tags are called sclerites; fleshy in the centre and hard on the exterior due to a layer of conchiolin (a protein secreted as a part of shell formation) covered by a layer of iron sulphide that gives it a black metallic appearance (fig. 2). The iron sulphide exists in two forms in the snail: greigite, which is highly magnetic, and pyrite, which is commonly known as fool's gold. The presence of the metallic sclerites is not totally understood but Suzuki et al. at the Extremobiosphere Research Center in Japan suggest the snail may control the mineralization of the iron sulphides for protection from crab predation or perhaps for detoxification purposes.

Completely unique is that the iron sulphide is also found in the snails' shell, so this was the first discovery of an animal with iron sulphide in its skeleton (fig. 3). Underneath the metallic exterior there is a thick but softer organic layer which covers the hard calcium carbonate shell that most marine snails have. So unusual is this triple layering in the shell, in both its chemical make-up and mechanism, that some scientists consider it to offer extensive protection and think it may be used as inspiration for man-made armour in the future.

New vent fields, new discoveries

The iron and sulphide found in the scaly-foot gastropods at the Kairei field comes from the mineral rich waters expelled from the hydrothermal vents and black smokers. Different vents do, however, have different mineral compositions. Nevertheless, it was still of great surprise when in 2009 the Solitaire field was discovered in the Indian Ocean and living on it was a different colour form of the scaly-foot gastropod; this time displaying a brown shell and cream coloured sclerites, both completely lacking the iron sulphide coating. Genetic testing by Nakamura et al. at the Precambrian Ecosystem Laboratory in Japan confirmed in 2012 that they are the same species and also that the sclerites of the iron-lacking form were in fact mechanically stronger. Then, in 2011, yet another population of the black scaly-foot gastropod was found in great abundance at the Longqi field, another new discovery for the Indian Ocean, and this is where the two specimens deposited at this museum came from. Figure 4 shows snails from the three different vent populations.

The heart of a dragon

The external features of this snail are certainly spectacular and strange, but taking a look inside shows that the theme continues there. It is of no surprise that this snail has special adaptations to live in such a toxic and harsh environment; survival in such a place certainly requires an evolutionary helping hand. Similarly to other species living on black smokers and close to vent effluents it has evolved a symbiotic relationship with bacteria living inside its body. These bacteria supply the snail with most of its nutrition and to accommodate them the snail has developed a massive oesophageal gland, taking up over 9% of its body mass! In turn the snail needs to keep the bacteria alive and so has also developed a huge circulatory system, including a supersized heart, to supply the oesophageal gland with enough oxygen. It's a win-win situation, or perhaps a deal made in Hell!

What's in a name?

Although it was discovered 14 years ago it is only this year that the scaly-foot gastropod was officially christened Chrysomallon squamiferum by Chong Chen of Oxford University and his associates. This snail is so different to any others known that Chen et al. needed to describe a new genus to put this new species in. The genus name Chrysomallon means 'golden fleece', giving reference to the metallic coating often containing fool's gold. The species name squamiferum means 'scale-bearing', making obvious reference to the sclerites covering the foot of the snail. The process of describing new species also means that a specimen (holotype) or a series of specimens (holotype and paratypes) need to be selected as representatives of the species and placed in museum collections, and that is where we come in! The two specimens we have been donated are a part of this incredibly important 'type' series. They even came with a note telling us to store them in 100% alcohol as any water in the preservative would cause them to rust over time. Rusting is certainly not a conservation issue we usually have to consider with our mollusc collections!

Back at the museum

This is not the first addition of molluscs from deep sea hydrothermal vents to our collections. With resident bivalve researchers working here we already house material that has been described by our experts from such environments, in addition to other extreme marine environments. Some are from the oil seeps off Louisiana in the Gulf of Mexico, the mud volcanoes in the Gulf of Cadiz or methane seeps off Chile. Others are from hydrothermal vents on the Northern Mid-Atlantic Ridge and hydrothermal springs in the Cascadia Basin of the NE Pacific. Perhaps the strangest place that one of our new species was described from was the wreck of the sunken ship Francois Vieljeux which contained organic cargo containing sacks of beans, sunflower seeds and bales of sisal twine. Over time the rotting cargo produced a sulphur rich environment that attracted animals able to exploit it, including the bivalve Spinaxinus sentosus Oliver & Holmes (fig. 5). Amazing.

When you think that only 160 years ago much of the scientific community embraced Edward Forbe's 'azoic theory', that life could not exist beyond 550m, our knowledge and understanding of the sea has really come on a very long way. Nevertheless, there will always be more waiting to be discovered.

If you want to learn more about our collections follow us on Twitter @CardiffCurator

References:

Chen, C., Copley, J. T., Linse, K., Rogers, A. D. and Sigwart, J. (2014). Abstract from Seventh Congress of the European Malacological Societies. Edited by White, T. S.

Chen, C., Linse, K., Copley, J. T. and Rogers, A. D. (2015). The 'scaly-foot gastropod': a new genus and species of hydrothermal vent-endemic gastropod (Neomphalina: Peltospiridae) from the Indian Ocean. Journal of Molluscan Studies. 81(3): 1-13. doi:10.1093/mollus/eyv013

Nakamura, K, Watanabe, H, Miyazaki, J, Takai, K, Kawagucci, S, et al. (2012). Discovery of New Hydrothermal Activity and Chemosynthetic Fauna on the Central Indian Ridge at 18u-20uS. PLoS ONE 7(3): e32965. doi:10.1371/journal.pone.0032965

Oliver, P. G. & Holmes, A. M. (2006). New species of Thyasiridae (Bivalvia) from chemosynthetic communities in the Atlantic Ocean. Journal of Conchology. 39(2): 175-183; figs 1-32.

Suzuki, Y. et al. (2006). Sclerite formation in the hydrothermal-vent 'scaly-foot' gastropod - possible control of iron sulphide biomineralization by the animal. Earth and Planetary Science Letters 242. 39-50.

Yao, H. et al. (2010). Protection mechanisms of the iron-plated armor of a deep-sea hydrothermal vent gastropod. Proceedings of the National Academy of Sciences 107.3 (2010): 987-992. http://dx.doi.org/10.1073/pnas.0912988107

Every week we tweet about molluscs on #MolluscMonday via our @CardiffCurator Twitter account. This is a great opportunity for us to showcase some of the amazing specimens in our collections at the Natural Sciences Department of National Museum Cardiff. We also talk about some of the research work we do and highlight some of the fantastic molluscs that are out there.

So why not find out what we have been tweeting about over the last few months in our latest Storify Story 'Stunning Shells'.

If you find these interesting you can also follow us on Twitter.

And why not follow our Natural History conservators as well @NatHistConserve

The first ever National Meadows Day is tomorrow, Saturday 4th July. You may have noticed National Museum Cardiff now has an Urban Meadow on the east side by the Reardon Smith Lecture Theatre. It gives us a fantastic new outdoor learning space where just a lawn used to be. Check out our programme of events based around the meadow in What's On.

Our Urban Meadow with the bee hives on the roof is a positive approach by the museum to increase pollinators within Cardiff and are funded entirely through landfill tax. Meadows on our other museum sites help pollinators throughout Wales. With a no dig, no chemical policy, as well as introducing plants and seeds from Flora Locale recommended suppliers, we are following sustainable principles. 

Children have used the Urban Meadow to start investigating the natural world, children who may not otherwise have visited a museum. The next event is ‘Family Fun in the Meadow’ on Saturday 11th July: Help our OPAL scientist to survey the bug life in our urban meadow and learn to be a botanical illustrator. See the What’s On guide for further information

You can find further information and links to events for National Meadow Day on the Plantlife webpages

Also you can follow the Twitter hashtag: #magnificentmeadowsday

By Sally Whyman and Kath Slade

We have created word clouds based on the most commonly used terms in the responses to two questions on display in the exhibition. Figure 1 shows the feedback to the question "Which object would you recommend to a friend?" and Figure 2 shows the terms used to the query "How do you feel surrounded by so many fragile objects?".

We hope to periodically produce these word clouds; they may show that the most frequently used terms change over time or that they remain the same. Interesting conclusions could be drawn from either. If they change it could be that people will appreciate certain works due to the time of year, the likelihood that they attended an event or changing fashions. If they remain unchanged the conclusion could be drawn that some works resonate strongly with the majority of visitors.

The questions are posed using two methods on the landing of the west wing galleries; as a comments section on the iPad's and a bulletin board with paper and pencils provided to write a response (Figure 3).

These questions were posed to combat the standard "What do you think of the exhibition?". Rather we wanted to create questions which would encourage key concepts of the exhibition: to stimulate curiosity and encourage debate. This (we hope!) will happen through visitors reading the questions and considering their own responses and by seeing the responses of others which are left on display in the space.

Excitingly we have found visitors have taken to this style of questioning; the responses to the question about recommending an object to a friend (on the "bulletin board") have been through text and images with some visitors expanding upon why they like certain works (Figure 4) . In the comments field on the iPad's which asks about personal experience in the exhibition we have been interested to seeing the varying reactions. Such as a visitor on the 5th May who responded: "Scared worried but its lovely" or from the 16th May "I really liked the pull between wanting to touch and not being able to touch. When i stepped into the first installation i was overwhelmed with a child like want to feel and discover for myself.".

Let us know If you have any comments on the exhibition, questions or if there's a subject you'd like to see a future blog post about. By Penelope Hines & Jennifer Dudley

‘Drown’d in drowsy sleep, of nothing he takes keep’. These were the words that William Goscombe John chose to accompany his sculpture Morpheus when it was first exhibited at the Royal Academy in 1891.

The caption was taken from the 16^th century poem The Fairie Queene by Edmund Spenser, although it is not a direct quotation. This epic allegorical poem follows the journey of several Arthurian knights as they battle their way through a mythical fairyland.

Morpheus, the Greek god of dreams, plays a small role in The Fairie Queene. He is called upon to help the black sorcerer Archimago trap Redcrosse, one of the Christian knights. He does this by conjuring up a false dream of love and lust to fool Redcrosse into believing that his lover Una has been ‘sporting’ with another knight. This leads to Redcrosse abandoning her and continuing his quest alone.

In this sculpture Morpheus is shown asleep - or perhaps softly stirring from sleep, his arms stretched languidly above his head. Apart from this, John makes no other reference to the narrative of The Fairie Queene and it is not clear why he would have chosen to depict a figure who plays a relatively small role in the story, and in Greek mythology.

We might say that the mythological theme was a pretext for depicting a nubile male nude. Alternatively, we might see it as a statement about the role of the figurative sculptor. In mythology, Morpheus had one great power: he could mimic the human form, and trick people into seeing physical bodies that are not really there.

Stephanie Roberts and Penelope Hines