Wednesday, 31 July 2013

Reaching Out for New Blood


 
Those of you who know me will be aware that I have always been a fisherman. I was lucky enough to have a father and family who would take me from time to time as I learnt the techniques and skills required to be able to fish effectively. Those early days of fishing, using a float, with very primitive equipment (we did not have a lot of money in those days) and using bread, cheese and bacon rind to catch crucian carp out of a farmers’ pond are amongst my most cherished memories as a child.
As the years wore on I became a more refined angler and the fish got bigger. By the time I was sixteen fishing was my passion and I spent as much time going as I could. At least once, maybe twice a year, my friends and I would go fishing for a whole week – nights and all. And as I began my working life I could afford to go to better fisheries and buy more advanced and more efficient equipment.
For a long period of time, fishing dominated my leisure time but gradually things began to change and catching became the be all and end all. It was a numbers game – the most fish, the biggest fish, and if I didn’t catch it was common for me to feel quite down about it – and as I tried harder and harder I actually caught less and less. Eventually I realised I was not enjoying it anymore and then I remembered that fishing was actually meant to be a pleasurable past time and that relaxing and enjoying nature  was what it was meant to be about.
So I went back to basics and did some float fishing and river fishing and this soon got me back to where I should have been – enjoying myself. I carried on fishing for big fish but the numbers game disappeared and I did not HAVE to catch – it was just not that important anymore. As a result fishing was a pleasure once again and I have actually caught more and bigger fish because I completely turned my attitude around and remembered what fishing was all about.
What on earth has this got to do with palaeontology I here you say? Well this brings me nicely to today. My fishing days now are not as frequent as they once were because of my passion for palaeontology and blogging, research, fieldwork, conferences etc. takes up a lot of my time but I do still go and it is nice to be sitting by a pool somewhere and fishing in a tranquil environment and, more often than not, it is simple float fishing I do and it is a very pleasurable way to chill out.
Recently it was announced that the number of youngsters taking up the sport of fishing have plunged alarmingly. Fishing in the UK was always known as the nation’s biggest participant sport – but not anymore. The numbers of youngsters fishing now has dropped by 44% since 2009 and the number of adults by 21%. This has other implications as well, particularly from an environmental point of view, but why has this drop in numbers occurred?
Well one of the factors, I am sure, is the apprenticeship factor. Many kids today start off with the latest gear, the latest baits and fish the best waters and I know many who have caught so much, so quick, that they soon lose interest and give up the sport in a few years. Starting off slowly using traditional methods and learning the art of fishing – an apprenticeship -  would almost certainly give them a greater understanding and an appreciation of everything around them in the natural world. They would always have been an angler.
Secondly, in a survey, children cited boredom, television, computers, game consoles and mobile phones as primary reasons for not wanting to go fishing. Interestingly, the same factors also dominate adults’ responses as to why they have given up or not taken up fishing. The knock on effect of this is that if adults cannot be bothered then children tend to follow suit. This is not a dig at any particular group of people but rather an indication of how society evolves in tandem with technological advances – it happens.
I don’t have children so I do not pretend to know all about kids and, not being a parent, I would never presume to tell anyone how to bring up their children. But on the odd occasion when I have been able to talk dinosaurs and fossils with them I am always delighted by their response. As part of a local geological society I took part in open days where we had a stand to encourage recruitment in the society and engage the general public in discussion. We had various displays of rocks and fossils with posters and hand outs to explain some of the more common aspects of both geology and palaeontology.
It was always the children who consistently talked more and asked questions and I was constantly amazed at how much some of them knew and how, quite often, they surprised their own parents with the depth of their knowledge. It came as no surprise then, that the most popular part of our stand was a shallow box filled with sand and pebbles in which we hid various common rocks, minerals and fossils in for the children to dig up.
 
No - not our little box but rather a professional exhibition displaying how an
excavation may look. 

The first year we did this we ran out of our stocks within a couple of hours. The following year we brought more but the kids thirst for this was insatiable and still we ran out – they absolutely loved it. The point is that children love rocks, fossils and dinosaurs and when they are encouraged at an early age it should be something they carry with them for many years to come but, for reasons we have already mentioned, this appears not to be happening.
Of course, this does not apply to everyone and I take great pleasure seeing children being taken out by their families and during school trips that encourages them to observe and appreciate the natural world – both past and present. In the UK, there are various clubs and societies that are doing their best to attract more young people into the earth sciences but I always get the impression that they are fire fighting. It is a fact that many of these organisations are suffering the same problems as angling is – their membership is declining and the amount of young people participating has dropped right off.
Indeed, when you attend any meetings that are run by these organisations, field or lecture, the demographic curve would clearly demonstrate that the majority of participants are mainly over 40 years old – my experience is that most people are significantly older than that. Perhaps the biggest exception to this is the Discovering Fossils  crew led by Roy and Lu Shepherd and their field meetings, which are very family orientated and open to all, are always heavily subscribed to so there is obviously some appetite out there. 
To be fair, the Discovering Fossils crew do a great job but if you look at the range of their field trips this year they are all at the same location – Beachy Head. This is problematic for them and certainly not their fault since the only reasonable locations available for these field trips are costal locations because, as I have frequently mentioned on this blog, the amount of inland venues and quarries that remain open has significantly diminished and the rabid health and safety culture of today virtually ensures no children are permitted. Indeed I know of only one quarry of my acquaintance that permits children on organised visits – otherwise it’s over 18’s only.
The other by product of this is that the popular coastal locations get incessantly searched and many now are quite desolate of fossils until the winter storms return and we get the much desired autumnal and spring tides to scour out the beds. So then you get this bizarre situation where even families who want to encourage their children to look for fossils actually find nothing and find their confidence taking a knock.
The point I am making here is that all hobbies, pastimes, clubs and societies, and many other interests are all suffering the same symptoms – falling membership, lack of interest, competition, and, most important of all, a lack of young people getting involved. To illustrate the problems facing us all, and only a year after the Olympic Games, we find the arguments over the games legacy have risen to the surface and what the affects and implications for the general public are. Did more people take up sport? Did the games encourage people to become fitter? Did community gain from the obvious effects of what was a wonderful occasion?
Initially, in the immediate aftermath, the effects were positive but already things are starting to tail off and there is a real danger that unless we mobilise the overall positive effects from the games that the trend will continue downwards. Only cycling, which was on an upward surge anyway prior to the Olympics, is booming. This is not a downer on the games or the premise of so many good things to come out of the Olympics but rather it does point out that even with enormous funding and a massive amount of good will that nothing is guaranteed.
In other words we are all in the same boat and everybody, regardless of what discipline is involved, is struggling to attract new interest – but especially children and young people. This is not going to get any easier but it is essential that we keep palaeontology and other earth sciences in the public eye as much as possible, whenever possible. We have to ensure that we are at the forefront in the race to cultivate more interest and get more people involved otherwise we risk losing out.
Despite all this, we are blessed in palaeontology that we have so many wonderful people and organisations that consistently make a contribution by being in the public eye and also involving the public.  Free time is often given up, often no fees are taken and the amount of work that is often attached to these contributions is considerable. Communication to the public is something we should all have a vested interest in and we can all make a contribution no matter how small and at what level.
And best of all, and our ultimate weapon, is that we have the dinosaurs and other fascinating prehistoric creatures in our arsenal that ensure continued interest in our science. Coming up later this year we have the Walking With Dinosaurs movie and, in 2015, Jurassic Park 4 and regardless of whether they are scientifically accurate or how dodgy the story lines are or how good the effects are, they will put dinosaurs, and thus palaeontology, back into the public eye. Thousands and thousands of people will see these films and this period will represent another golden window of opportunity to promote our science. We must ensure that we take advantage.

 
 

Thursday, 18 July 2013

Why Taphonomy Matters




You have often seen me use the phrase “taphonomic distortion” to describe bones that have been crushed or altered to a degree during the fossilisation process. And yet taphonomy is often overlooked in favour of the more glamorous side of palaeontology as we tend to focus on the various skeletal remains displayed before us and wonder about every aspect of how these animals may have lived and died.
But that’s alright and we all do it and, indeed, there is nothing wrong with focussing on the animal since that is what palaeontology is – the study of ancient life. And yet the discovery of something like a dinosaur skeleton is so much more all-encompassing since there is a huge amount of detail in the quarry that needs to be retrieved and/or recorded. Taphonomic detail is a vital as the fossil remains themselves and can reveal a wealth of essential data. But what is taphonomy?
Simply put, taphonomy is the study of the processes that enabled living organisms to become fossilised. We need to understand these processes so that we can better understand a more complete picture about our long dead animals and, of course, the environment in which they lived.
There are many factors that are included in the taphonomic process. For example, were the remains transported after death? What was the process of decomposition? How did the remains get buried? What was the rate of compaction? What other processes were involved? What were the chemicals involved? How did permineralisation take place? The questions are endless…..
Taphonomy also throws up some other words and phrases that are difficult to follow – especially to the layman. For example what happens to an organism once it dies and ends up being buried is known as biostratinomy. Another oft quoted word is the process of diagenesis which is more of a geological term to describe changes to rocks during both their formation and afterward but has been used by palaeontologists to describe how organic remains are transformed after they have been buried. 
My interest in taphonomy was sparked by the sometime amazing contrast in bone preservation in the same quarry. No matter how consistent fossil remains in a certain formation appear to be there are always anomalies and I am constantly aware not to get over confident when extracting fossils and also when preparing them. I am also always amazed how different the preservation can be in a single bone with one part being solid, well preserved and easy to prepare whilst the other end can be a crumbling mess that is a preparator’s nightmare.
But taphonomy not only reveals what may have happened to an individual animal but can also provide a wealth of detail regarding the environment it lived in. Numerous samples of the surrounding matrix within and around the quarry normally reveal microfossils – both plant and animal – which provide extensive data and enables a micropalaeontologist to build up a pretty accurate picture of the climate, the flora and fauna alive at the time.
As taphonomy goes, I have only scraped the surface of this fascinating and very important aspect of palaeontology. Anyway, as a palaeontologist, I should darn well have an interest in taphonomy if I want to understand more. For the record, some of the best papers I have read are Raymond Rogers’ work on the Two Medicine and Judith River Formations (1990, 1998) and Anna Behrensmayer’s 1988 paper on vertebrate preservation in fluvial channels – essential reading for any budding taphonomist out there.
The reason for this little venture into taphonomy was inspired in part by a new paper recently published by Frankie Johnson, of Montana State University, and her colleagues looking at the taphonomic influences on the incredible sauropod nesting site at Auca Mahuevo situated in Patagonia, Argentina. Professor Johnson is something of a specialist when it comes to fossilised eggs and the sedimentological processes that affect them and she has performed extensive field work at the locality.
Auca Mahuevo, if there is anybody out there who does not know of this amazing site, was discovered in 1997 by Luis Chiappe and his crew and has become one of the best known dinosaur nesting sites in the world. It is Upper Cretaceous in age and exposes terrestrial fluvial deposits of the Anacleto Formation.
The deposits at Auca Mahuevo are composed of fine grained mixed load siltstones, sandstones and mudstones which were deposited in floodplains and channels under semi-arid conditions during alternate wet and dry seasons. In these deposits are found tens of thousands of titanosaur sauropod eggs with various degrees of preservation but these do include those with embryos inside and there are even patches of wonderfully preserved embryonic skin that clearly displays the scale patterns and their various morphologies.
The study area features four distinct egg-bearing layers representing four different sequential nesting time periods. Sauropod skeletal remains are also found – in between egg levels 3 and 4 and also within level 4. The team wanted to know what affect vertisols, pedogenesis and the resulting taphonomic movement may have had on both egg morphology and the overall size and shape of an individual nest.
Pedogenesis is the term for soil creation and a vertisol, whilst not a palaeontological term per se, is a soil which has high clay content. Development of vertisols takes place today and the alternating temperatures in both wet and dry conditions cause this clay to shrink and swell which in turn leads to soil movement.  This movement can be both vertical and lateral and creates visible features known as slickensides, microhighs and microlows. Slickensides are smooth, sometimes polished surfaces, which are caused by soil movement between two surfaces and are often accompanied by a striated surface which is indicative of the direction of travel. Microhighs and lows are the resulting deposits of sediments, both upward and downward (high and low), caused by soil movement and cracking.
Partial egg on polished slickenside indicated
 by arrow (From Jackson et al 2013)
 
Sauropods used the floodplains for their nesting grounds and these were subject to flooding events which buried the nests and eggs. While this was catastrophic for the eggs and the embryos they contained it was spectacularly good fortune for us as these wonderful eggs survived as fossils. It is very easy to look at these clutches, see how they are situated and count the amount of eggs they contain and get a reasonable idea of clutch size and behavioural implications. So it would appear……
But this study reveals just how dangerous it is to take any fossil remains at face value without taking everything else into account. Vertisol development and the effects of pedogenesis had profound effects on the eggs and nests of Auca Mahuevo. Movement of eggs resulted in various changes in shape, size, shell thickness and ornamentation (amongst others) and this has parataxonomic implications especially when identifying oo-species. At the same time these changes also affect things such as egg volume and pore morphology which affects and influences incubation hypotheses.
Perhaps the most significant consequence of this sedimentary travel is the displacement of eggs from their original position in a clutch so that we have clutches that may be missing eggs or, indeed, have clutches that have combined to falsely increase the total number of a clutch. Not only that but there are clutches mixing from different stratigraphic horizons which further distorts the data.
Despite the enormous amount of fossil eggs involved at Auca Mahuevo there is hardly any evidence of a true nest – except for a few traces. Because of the enormous pedogenic vertisol disturbance over the many hundreds and thousands of years after the eggs were laid and then buried, evidence of nests has been mostly obliterated and this, in combination with the random displacement and distortion of the eggs makes behavioural hypotheses difficult.
With this enormous amount of post burial disturbance it is difficult to postulate the exact shape and size of the eggs, how they were laid and how big a clutch may have been. Since many dinosaur nesting sites are located in a floodplain environment, the authors stress that it is absolutely essential that an accurate record is made of those nests that are in situ and relatively undisturbed, as well as those that have been subsequently changed   by pedoturbation and vertisol development (pedoturbation is the changes that take place to alluvial sediments that are not caused by the redistribution of water).
The authors back this up with a list of nine separate processes that should be followed when investigating any dinosaur egg-bearing strata and suggest that these guidelines will enable future workers to produce a much more comprehensive and accurate assessment about sauropod reproductive behaviour.
I liked this paper very much and learnt quite a bit which is always good. And, more than that, it is a timely reminder that when any fossil remains are found that it is essential that ALL details are recorded, that everything is taken into consideration and that not everything is as all that it may seem to appear. 

References
Behrensmeyer, A. K., 1988. Vertebrate preservation in fluvial channels.  Palaeogeography., Palaeoclimatology., Palaeoecology., 63:183 - 199.
Jackson, Frankie D., Schmitt, James G., Oser, Sara E., Influence of Vertisol development on sauropod egg taphonomy and distribution at the Auca Mahuevo locality, Patagonia Argentina, Palaeogeography, Palaeoclimatology, Palaeoecology (2013), doi: 10.1016/j.palaeo.2013.05.031
Rogers, R.R. (1990). Taphonomy of three dinosaur bone beds in the Upper Cretaceous Two Medicine Formation of northwestern Montana: evidence for drought-related mortality. Palaios, 1990, V.5, p. 394 – 413.
Rogers, R. R. (1998). Sequence analysis of the Upper Cretaceous Two Medicine and Judith River formations, Montana; nonmarine response to the Claggett and Bearpaw marine cycles. Journal of Sedimentary Research. doi:10.2110/jsr.68.604