Rain, rain, rain, rain, rain,.....and mud!

The raindrops in South Dakota seem to disobey the laws of physics when it comes to the fundamental hydrostatic bonds that define and constrain a single falling drop of from the skies. Here, or so it would seem, the drops coalesce into bucket-sized ‘orbs’ that have the ability to disinter whole dinosaur bones from their Hell Creek tombs…maybe we should replace our geological hammers with water cannon?  The frustrating cycle of thunderstorms with intense rain, followed by a brief blast of sun, is making access to our field sites impossible…or I should say impassable. Once you step-off the prairie onto the series of inter-bedded sands and muds…the muds seem to be instantly attracted to your boots. The cumulative effect of successive steps results in 50-pound buckets of mud attached to each limb, making walking a cumbersome and exhausting process. I look over my shoulder at our tracks and it appears that a 400-pound animal has been dragging its huge feet slowly through the Badlands…no doubt a Sasquatch-type legend will soon be born of the Hell Creek. The once crackly popcorn surface of bone-dry mud is now replaced with glistening streams of mud and sand, gently ebbing into larger hollows to help mire any unsuspecting cows, antelope, deer or palaeontologists. We often include in our lectures how mobile the Badland landscapes and environments can be and that erosion and weathering are the worst enemies of fossils…I never thought I would be stuck in the very processes that carves and shapes the very same landscape. It is August…the supposed driest month of the year.

Hail palaeontologists!

Wherever there is a yin…there is always a yang. Manchester has had beautifully sunny weather these past few weeks…the rain has moved to South Dakota. This is great for the ranchers…as they can now look at their green pastures and fattened calves. The Great Plains are a sea of green, interspersed with ephemeral lakes, rivers and waterfalls…and that’s just the highway! Yesterday we saw stormy skies that hurled golf-ball sized hail with a soupçon of tornado. This is going to be a slippery field season.

 

Hail!

On the downside, the mosquitoes have multiplied to biblical proportions and seem to be vying for position as top-predator in the local food chain. The said blood-sucking savages are so fat on the blood of cows, ranch hands, Sturgis bikers and now…me. Yes, the mosquitoes were so happy to smell the blood of an Englishmen; they did a fly-past in formation. I felt I was partaking in some bizarre air-show, in which I was the food-stall for the participants. The said beasties could choose to drink straight from the skin, or take an alternative slurp of haemoglobin through my T-shirt, hat or trousers…these vial creatures seem to disobey all laws of biting…quite unsporting!

 

The long and 'green' march from site to site.

As soon as our team exited our field vehicle, the swarms descended. Within a few seconds we were all swatting at anything that buzzed. This is the first field season for Dr. Nick Edwards and Dr. Charles Egerton…the rest of the team did not dare to say that the mosquitoes were worse than we had ever seen. Dr. Bill Sellers and Dr. Victoria Egerton batted the said beasties away…one even kindly bashed a mosquito on my left shoulder…reminding me of my torn rotator cuff…double ouch! The bite of the day had to go to Jennifer Anne (aka Indy), as she was bitten on the lip…soon swelling into a curious mix of snarl and pout. Once we had donned all our field gear, we headed to the ridge above our SUV where we had parked. We were greeted with a splendid view of beautiful Hell Creek Formation badlands, set amidst an ocean of green; gently swaying in the afternoon breeze…here begins another field season.

Twas the night before fieldwork...and everything was heavy

All I can see in my office is a vast pile of equipment, ranging from laser scanning units to trenching tools. Each time a nervously glance at the luggage, I hear myself sigh. Why do we have so much 'stuff'. I am sure that last year's field season did not require so much kit? However, my main concern is the 'final frontier'...as 'space' is rapidly dissolving in my densely packed luggage. It is one of those moments that you start to wish for a Tardis-like bag to swallow all kit, but at the same time generate an internal anti-gravity zone within the confides of the luggage. I pick-up my first piece of luggage and groan; it seems impossibly heavy. I check inside the bag for any stray neutron stars that might be lurking in the darkest recesses, anchoring this stellar remnant to my office floor....to add to my fun, this year I am hampered by having one functional arm (courtesy my a shoulder injury from the 2012 field season). It seems remarkable that by just starring at the pile of kit or closing my eyes to the shear lack of carrying capacity, this does little to help me. This is when you inevitably start the pairing-down process, isolating those non-vital pieces of field equipment, such as soap, deodorant or underwear. Just as you think you are nearly there...you spy a pile of cable's, plugs and connectors...without which the mountain of multiple electronic gadgets will silently mock you and refuse to communicate. The travelling electronics store also boasts a significant computer section, with PC's Macs and netbooks gradually piling-up. Oh for a single plug/cable/software solution...isn't technology meant to be making our lives easier? Why does my bag now look like a bloated organism riddled with escaping tape worms...the abstruse wonders of 21st Century fieldwork.

Nature's Chemical Laboratory

The brilliant 18th Century chemist, Antoine Lavoisier (1771-1794), is quoted as saying, 'I consider nature a vast chemical laboratory in which all kinds of composition and decompositions are formed.' It is often folly to paraphrase the accepted genius of Lavoisier, but the work that we undertake at particle accelerators (such as Diamond and SSRL) has enabled us to extend this chemical insight to life through deep time. It might now be fair to say, 'We consider nature, both past and present, a vast chemical laboratory in which all kinds of composition and decompositions are formed, which are occasionally preserved as fossils'.

What organic signals might remain in a fossil...even those not locked in amber?

The study of decaying bodies has provided useful data on the various stages of decomposition that might give clues to the time and type of burial environment.  It is remarkable that as soon as a heart stops beating, oxygen that was so critical to life process ceased to circulate and internal anoxic conditions rapidly develop. In the absence of oxygen cells began their auto-destruct sequence, this is called autolysis. Here the cells self-destruct courtesy of enzymatic digestion. While the tissues of an organism are still relatively soft, prior to rigor mortis setting in, blow and flesh flies all take there chance to colonise a corpse with their eggs and soon to be voracious larvae (who we know and love as maggots).  

 

Tissue chemistry of living animals provides a useful elemental recipe to diagnose and then identify in fossils.

If there are no scavengers around to chomp through our dead body, fly maggots will soon compensate for this. Within 24 hours flesh can often be moving again, not in a zombie-like state, but with the writhing bodies of maggots, feasting on rotting flesh. Maybe I should have suggested at the beginning of this blog that you not read this close to meal times? Whilst the maggots are munching from within a carcass, soil microbes start the process of multiplying on the new food source beginning to ooze from the various orifices of a body into the underlying soil. Microbial communities that were once symbiotic with an animal in life, living in the respiratory system, gut and intestine, also begin to multiply and consume their host. This is the ultimate in organo-recycling systems. The organic acids and gases (including methane and hydrogen sulphide) generated as by-products of the microbes metabolism soon begin to change carcass colour and start to bloat the body, accompanied by the distinctive rotting smell...as my anatomist friend Dr. Dino Frey might say, 'It has all gone soft and soupy'.....we all have days like that!

Decaying modern carcasses can provide evidence as to how fossils might preserve delicate organic molecules.

The combined efforts of insects, microbes and possibly scavengers would make short work of our deceased beastie. Most of the body fluids would soon be 'released' into the surrounding soil, causing an initial dye-off of vegetation (due to nitrogen toxicity), leaving a deathly halo around the body. The maggots would pupate soon after having eaten their fill. All is quiet on the recycling front to the causal observer, but not to the geochemist, as things have only just started to get interesting. Depending on the soil porosity and permeability beneath a body, the sediments would also be directly affected by the gentle ebb of decay juices from the body...yum! As the soil microbes get a free dinner, they also begin to process the vast influx of nutrients from the carcass. Metabolic by-products of the microbes also begin to alter pore-water chemistry, giving rise to the precipitation of early mineral cements to bind the soil particles. The stink of decay marks the availability of reactive chemistry. The once living animal is now entering the immortal realm of fossilisation.  The bodies of all living organisms are a wonderful store for elements that once released (or partly released) from their biological bonds can complex to form different species of mineral. Here is the paradox. Release too many of the organic building blocks to the inorganic processes and you reduce the amount of organism that remains to be fossilised. This is a bizarre 'two-horse' race between decay and fossilisation...one that we rely on being a close draw.... especially if we are to search any fossil remains for a whiff of original biochemistry that might still lurk within the mineralogical straight-jacket. This is precisely why we need to use some of the most sensitive imaging technology in the world to tease-out this astoundingly dilute organic signal, through working at synchrotrons light sources such as Diamond and SSRL. Splendid fun!

Diamond is a Palaeontologists best friend....

I can already hear the gentle hum of nudged particles circumnavigating the vast Diamond storage ring at relativistic speeds....yes, once more the Manchester Palaeontology Research Group are headed to the UK Synchrotron facility. We have spent the last few weeks preparing our prehistoric samples for the ultimate examination, one that takes place at the atomic scale. We aim to tease dilute traces of past biochemistry from our fossils using the astoundingly bright monochromatic x-ray light that only an accelerator can generate.

This weekend we will be working in the realm of Extended X-ray Absorption Fine Structure spectroscopy (or EXAFS for short). EXAFS spectroscopy is sensitive to the electronic structure of the probed central absorber atom, and is especially able to accurately quantify distances from one shell of electrons to the next surrounding an atoms nucleus. This technique provides a great deal of information as to the atoms biological or geochemical context. In other words, was the atom emplaced within the organism while it was still alive, or did a geological process place a strategic atom to later bamboozle palaeontologists. This is of huge importance when trying to understand the chemical ghosts of extinct organisms, given each atom has its own diagnostic fingerprint....and its our task to run those prints!

Another splendid year!

The class of 2013 from the School of Earth, Atmospheric and Environmental Science...I am the rather brightly clad chap at the front!

So you want to name a new species of dinosaur?

We often take for granted the elegant simplicity that a species name might take.  However, a name often provides the tag from which we can hang the evolutionary relationships and classification of an organism… so, it is worth explaining how and why we name beasties. To start somewhere we are all familiar with, a popular name. Palaeontologists have the rather fun habit of giving dinosaurs a nickname when excavating a skeleton…especially when the said remains are either rare, complete or both. The T. rex skeletons of Sue and Stan were named after their respective finders. The name for the mummified hadrosaur dinosaur that Tyler Lyson and I excavated a few years back, was based on the simple fact of its geographical provenance ('Dakota'). However, all types of birds, mammals (including ourselves), fish, amphibians, reptiles, crustaceans to bacteria have at least two 'official' names that follow internationally accepted codes for naming plants and animals. These are the International Code for Zoological Nomenclature (ICZN) and the International Code for Botanical Nomenclature (ICBN). Within these two books are the rules of naming a new species. A new name is given only when the plant or animal that has been discovered is shown to be distinct from any known species. The animal, its morphology, fossil and/or structure is then formally described and published within a peer-reviewed journal (that is usually the fun part!). A new species is then ‘born’ unto the blinding light of the scientific world, and often makes a brief appearance in the wider world, via the media….usually hailed at the end of the news programme by the words ‘And finally’…'And finally scientists at the University of Dunking Buckets have discovered the fossil remains of a new species of predatory dinosaur with feathers, etc. etc.’ Having feathers and being a predatory dinosaur usually ensures such stardom.

The classification of specific plants and animals into distinct groups or tribes is also worth a quick review. Carl Linnaeus (his name was really von Linne, but he even translated his own name into latin!) devised the binomial ('two-name') system applied to naming plants and animals in his splendid work Systema Naturae, published in 1735. Linnaeus subdivided a name into first the genus and then species names, for example you are Homo sapian (written always in italics). The Linnaean system allowed species to be classified within a hierarchical structure, starting with kingdoms. Kingdoms were divided into Classes, then Orders, which were further divided into Genera, eventually divided into Species. The classification was based upon observable characters, meaning that many early classifications resulted in very strange family trees. The more specimens and morphological characters you have, usually the more robust the family tree...but this does not stop single bones representing a whole species. However, a new fossil or living beastie that possesses a very distinct character, say a theropod dinosaur with feathers and a peg-leg, can have an impact that is far from proportional to its evolutionary ‘importance’ in the fossil record of all life (such is the draw of toothy beasties with pirate tendencies).

Our own evolutionary path parted with the ancestors of dinosaurs some time in Carboniferous Period, when the diapsids (reptiles and later to include birds) and synapsids (to become mammals) parted evolutionary company. However, the basic tetrapod (‘four-feet’) skeletal plan is still recognizable, shared between vertebrates…even palaeontologists! I love taking my undergraduate class to The Manchester Museum across the road from my University Department in which I teach. Getting students to recognise the five fingers in the hand (pectoral fin) of a sperm whale (Physeter mcrocephalus), the vestigial hips (ilia) and seven neck (cervical) vertebrae and to compare with elephants (Loxodonta sp.), antelopes (Antilope sp.) and chimpanzees (Pan troglodytes), the conservative skeletal blueprint is such a splendid example of such shared relationships. The evolutionary distance between one animal to another is beautifully displayed by their morphological 'distance', a function of the selective pressures that have often dictated the survival of a species. There is no vim divinam at work, purely the elegant simplicity of ‘decent with modification'...as so eloquently put by Charles Darwin.