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Curator of Micropalaeontology's blog

4 Posts tagged with the palynology tag
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The Museum runs an After Hours event called Crime Scene Live that in February featured micropalaeontology curator Steve Stukins.

 

Micropalaeontological evidence is increasingly being used to solve major crimes. Read on to find out about Steve’s involvement in Crime Scene Live, how our collections could help forensic studies and how our co-worker Haydon Bailey gathered some of the evidence that was key to convicting Soham murderer Ian Huntley.

 

Botanical or microfossil evidence?

 

The following image is of modern pollen, so could be described as botanical rather than micropalaeontological evidence.

 

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A variety of modern pollen types similar to the ones investigated at the Crime Scene Live event.

 

As I mentioned in my post What is micropalaeontology?, distinguishing when something is old enough to become a fossil is difficult, particularly when some modern species are present in the fossil record. The Museum's microfossil collections contain modern species, particularly our recently acquired modern pollen and spores collection, and this collection has enormous potential as a reference for forensic investigations.

 

What can microfossil evidence tell us?

 

Because organisms that produce microfossils are present in a wide range of modern and ancient environments and can be recovered from very small samples, they can provide a lot of useful information. Mud or sand recovered from boots or clothing can show where the wearer has been and even the pollen content of cocaine can provide evidence of its origin or where it was mixed.

 

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A scanning electron microscope image of British chalk showing nanofossils.

 

These details can relate a suspect to a crime scene, relate items to a suspect/victim or crime scene and prove/disprove alibis. Evidence can also show cause of death, for example, diatoms or freshwater algae present in bone marrow can indicate drowning.

 

Microfossil evidence helps solve the Soham murders

 

Haydon Bailey, who is working temporarily at the Museum on a project studying our former BP Microfossil Collection, provided some key evidence that convicted Ian Huntley of the Soham murders.

 

Haydon identified chalk nanofossils on and inside Huntley’s car that were common to the track leading up to the site 30 miles from Soham where the bodies had been dumped. For details about all the scientific evidence used, this article on the Science of the Soham murders is an interesting read.

 

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Members of the public participating in Crime Scene Live activities.

 

Senior Micropalaeontology Curator Steve Stukins writes about Crime Scene Live at the Museum:

"This special public event gives the audience a chance to become a crime scene investigator for the evening using techniques employed by scientists here at the Museum. People are often surprised that the Museum is involved in forensic work, especially using entomology (insects), botany (plants) and anthropology (analysis of human remains). Crime Scene Live uses all of these disciplines and forms them into an engaging scenario for the visitors to get involved in.

 

Palynology, in most cases pollen, is used quite often in forensics. As pollen is extremely small, abundant and diverse in many environments it can be used to help determine the location of a crime and whether a victim/perpetrator has been in a particular place by understanding the specific pollen signature of the plants in an area.

 

Our jobs as forensic detectives in the Crime Scene Live Event were to determine where a smuggler had been killed, for how long he had been dead and the legitimacy of the protected animals he was thought to be smuggling. I’ll be giving away no more secrets about the evening, other to say that it was a great pleasure to be involved in a thoroughly enjoyable event and the feedback from the visitors was superb."

 

So if you fancy a bit of murder/mystery then why not come and help micropalaeontology curator Steve Stukins solve the Case of the Murdered Smuggler on 1 May or in October. Details of other Crime Scene Live events scheduled for this year can be found here.

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In January we transferred the Botany Palynology (pollen and spore) Collection to a new location within the micropalaeontology collections. The  collection includes 32,500 glass microscope slides and 155 files of images of pollen and spores from named living plants from worldwide locations. So why should we be interested in moving this collection to the Palaeontology Department?

 

This collection is already being used by Earth Science staff studying the contents of fossil hyena dung, evidence of early human agricultural activity and changes in the landscape over approximately the last 2.5 million years as a result of climate change. The collection also has potential for supporting forensic studies to help solve crime.

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Dr Tom Hill taking great pride in wheeling a trolley of pollen and spore slide cabinets past the giant Sequoia in the main hall of the museum. For health and safety reasons we were only able to move the collection before the Museum opened to the public.


 

In one of my first blog posts - what is micropalaeontology? - I mentioned that there is not always a clear distinction between fossil and extant (living) collections and this is very much the case here. This is an important collection for palynologists looking to reconstruct environments over the the Quaternary Period which covers approximately the last 2.5 million years as many of the plant species present today are represented in the Quaternary fossil record.

 

Pollen and spore grains have an outer wall of an extremely resistant material known as sporopollenin so are widespread in both fossil and recent terrestrial and near shore sediments. Most are smaller than 50 microns so relatively small samples can produce thousands of pollen grains of species diagnostic of particular climatic conditions.

 

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Some of Tom's Holocene core from Somerset, showing a lighter estuarine layer between freshwater peats.

 

Dr Tom Hill of the Earth Sciences Department at the Museum is analysing pollen from sediments from Somerset that cover the Holocene Epoch (i.e. the last 11,500 years).  He collected them using a sedimentary corer, which is essentially a larger version of an apple corer that is inserted into the ground to extract deposits preserved beneath our feet. He said, 'by taking sediment samples at regular intervals throughout the sediment sequence, you are able to develop ‘snapshots’ of what the landscape looked like every few hundred years.'

 

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Tom doing fieldwork with a sediment corer in a 'real field' at Shapwick Heath Nature Reserve.

 

The landscape changed in response to climate and human activity: an abundance of tree pollen suggests that woodlands dominated the landscape while shrubs, herbs and grasses infer an open grassland setting. 'Shifts from woodlands to grasslands are often indicators of human activity in the form of deforestation; the earliest cereal pollen found in these deposits is an indicator of the onset of agriculture during the Holocene' according to Tom.


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Hordeum secalinum - barley, BM10490. Cereal crop pollen grains like these are much larger than average (>40 microns), are typically round with a single opening (pore) and indicate periods of cultivation during prehistory. Photo Tom Hill.

 

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Artemisia - mugwort, BM8975_1. This species/genus thrives on bare ground with immature soil and is often found in sediments accumulated during cold periods such as late glacial episodes in the Earth's history. Photo Tom Hill.

 

Mark Lewis of the Ancient Human Occupation of Britain (AHOB) Project has been using the distribution of pollen from sediments and hyena coprolites (fossil dung), to reconstruct Quaternary environments. Coprolite pollen is useful in situations where sedimentary pollen is absent, for example in caves, where evidence of early humans is sometimes found. Pollen grains can occasionally be reworked from older sediments so analysis of coprolites alongside sediments associated with early human finds can be a useful test to see if the pollen has been preserved in situ.

 

Mark worked on pollen assemblages from Happisburgh, where the earliest evidence of human activity in Britain has been uncovered from c.850,000 year old sediments (for details of their publication in Nature see my previous post on what microfossils tell us about the early humans in Britain). These pollen assemblages showed the climatic setting of the finds and led to breakthroughs in the understanding of early human behaviour, adaptation and survival.

 

Both Mark and Tom are actively using this collection for their research by checking identifications of plant species represented by pollen in their samples. Catalogues, including 8 volumes published by the Northwest European Pollen Flora Project, provide 2-dimensional reference images of pollen but there is no substitute for examining museum reference collections like this one under a microscope. 'The collection provides the user the opportunity to look at numerous examples of an individual species present on a single slide, and review that species in multiple orientations' said Mark Lewis.

 

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Micropalaeontologists/palynologists Steve Stukins and Tom Hill examining the Northwest European part of the pollen and spore collection in its new home in the Palaeontology Building of the Earth Science Department.

 

The Northwest European part of this collection is particularly well ordered thanks to Dr Peter Stafford, Palynologist at the Museum until his death in 2009 who was a major contributor to the collection and publication of the Northwest European Pollen Flora volumes. He worked with many palynologists including Mark Lewis and Prof Steve Blackmoor, former Keeper of the Botany Department. As a result it is now possible to locate examples of the pollen and spores of a named Northwest European plant with ease.

 

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Tom in the old Botany tower examining some of the 155 folders of scanning electron microscope images of pollen and spores prior to their transfer to the Palaeontology Building.

 

The remainder of the 32,500 glass slide collection is currently housed in old metal drawers that do not conform to current storage standards and will need to be transferred into a cabinet next to the Northwest European collection. A start has been made by volunteers and students to rehouse the slides in special conservation grade sleeves but there is much work remaining to be done.

 

While I am very glad that this collection has been moved to our department, it would take me the rest of my career to carry out this task alongside the other collections management responsibilities that I have. As a result Tom Hill will shortly be advertising a couple of volunteer opportunities to help re-arrange the remaining part of this important collection.

 

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Slides of pollen from cannabis plants housed in special conservation sleeves in the Northwest European Collection.

 

Finding slides from cannabis plants jogged my memory to mention that while we anticipate that Quaternary palynologists will be the main users of the collection, there are applications for this collection beyond Palaeontology. Pollen grains present in mud on shoes or in tyre treads have been used to link suspects to crime scenes. This collection has potential to act as a reference for forensic palynologists as well as those looking to study the Quaternary.

 

Finally a big thank you to Tom Hill, Steve Stukins and Jo Wilbraham for help with transferring this important collection from Life to Earth Sciences and to Mark Lewis for providing details of the history of the collection and his research. The collection is available to - and will hopefully continue to be used by - both Life and Earth Scientists.

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Making a reference collection, taking high quality images of key species, identifying them and publishing the images on the web and in peer reviewed scientific articles are all ways in which expertise can be locked up in the Museum collections. NHM Scientific Associate Tim Potter has been doing just this during his time at the Museum. He studies acritarchs which are an enigmatic group of organic plankton that are present in marine rocks up to 3 billion years old.

 

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Some Lower Palaeozoic acritarch images created by Museum Scientific Associate Tim Potter. In general acritarchs range from about 5 to 200 micro meters.

 

Although we don't know exactly what acritarchs are (the name means unknown origin), they are very important organisms as many are probably primary producers and therefore could be responsible for generating oceanic organic carbon in some of the earliest oceans including the Cambrian Period roughly 500 million years ago. The Cambrian Period was an exciting time for the development of life with many strange organisms arriving and subsequently becoming extinct during the 'Cambrian Explosion' of life. Like many microfossil groups, the acritarchs have potential for dating rocks and subsequently the timing of some of these important events.

 

Acritarchs can also tell us about conditions in some of these ancient oceans; periods of glaciation and major oceanic carbon fluctuations are known to have occurred. Carbon isotopic studies of rocks suggest that the global carbon cycle was disrupted in the late Cambrian about 500 million years ago with increased carbon in the oceans at this time. This is referred to as the SPICE event but the link between this event and acritarch diversity is yet to be proven.

 

Tim studied acritarchs of Cambrian age for his PhD prior to a long career with Shell. After retiring he decided to publish the findings of his thesis and came to the museum to update his identifications using the amazing resources we hold like the John Williams Index of Palaeopalynology. In February, Tim published a key paper on acritarchs with co-authors Susanne Feist-Burkhardt and Museum PhD student Brian Pedder, expanding on work done by Brian for his masters project.

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Tim Potter, Brian Pedder and Susanne Feist-Burkhardt lined up by chance 'in publication name order' in the Welsh Borderland during a collecting trip for acritarchs.

 

Back in 2007, Tim, Susanne, Brian and myself carried out fieldwork specifically to collect samples to fill gaps in the Museum acritarch collections and to support Museum research that was being undertaken at the time. This fieldwork covered classic sites in the Lower Palaeozoic of the Welsh Borderland from the Cambrian to Silurian periods roughly 500-420 million years ago.

 

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Tim Potter collecting a sample from the bottom of a stream near Comley, Shropshire. There are very few exposures of Cambrian rocks in the world and in the UK you have to search hard to find potential sampling sites. This is not an uncommon situation for Lower Palaeozoic fieldwork in the Welsh Borderland!

 

To obtain acritarchs from the rock samples collected, laboratory processing using nasty acids like hydroflouric acid is neccessary. It is not a particularly strong acid but it is deadly as it dissolves pretty much everything apart from the organic constituents of rocks. Splash a bit on yourself and you would not last long! A laboratory with special fume cupboards and much protective clothing is neccessary for processing samples safely. Fortunately for Tim, these samples were expertly prepared by technician Jonah Chitolie.

 

Once processed, the residues were analysed by Tim and single specimens picked out so that they could be mounted and viewed on glass slides. Because the specimens are so small, this is a particularly fiddly technique that requires a lot of patience. Most slides of acritarchs are strew mounts; a small amount of processed organic sample is pressed and cemented between two glass slides using resins like Canada Balsam. For these types of slides, an assemblage is preserved rather than a single indentifable specimen.

 

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Some images of acritarchs from the Museum database.

 

The single grain slides that Tim produced have been photographed and the details and photographs released on the web via our specimen registration system. Tim has been happy with the identifications of most of the Cambrian specimens but would welcome comments on identifications of some of the younger Ordovician and Silurian examples. The Museum database is able to record re-identifications. It is hoped that other experts will log onto this resource and suggest alternative indentifications or back up the published indentifications, further increasing the value of this resource.

 

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The Palaeontology Department on-line specimen database search screen

 

To find these details, log onto our specimen database system and choose 'acritarchs' in the drop down list for 'fossil group' and click the box for 'images only' (as above). Tim is constantly adding more material to the collections so hopefully in the years to come this will develop into a very useful resource for students of acritarchs and help to ensure that important expertise is not lost.

 

Postscript. As I was writing this I was sent details of a PhD studentship on acritarchs based at the University of Lille, France.

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What is micropalaeontology?

Posted by Giles Miller Jun 21, 2011

The answer to this question is the straightforward part of this post: palaeontology is the study of fossils and micropalaeontolgy is the study of microfossils. Alas, that’s the easy bit done… what then, are microfossils?

 

I’ll assume that we all know what a fossil is (if not, I recommend starting here) so a microfossil must be a small fossil, right? Actually, this is a harder question to answer than you might think so here are some thoughts on how large a microfossil is, how old they are and how we manage them at the Museum.


Size

There is no agreed size below which a fossil stops being a large fossil and starts becoming a microfossil. Some people arbitrarily say that if you need to use a microscope to view a fossil then you are looking at a microfossil. However, some fossils we consider microfossils measure more than a couple of centimetres in diameter. The rocks that were used to construct the pyramids in Egypt contain microfossils that can be as large as a ten pence piece!


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Photo of Egyptian pyramid courtesy of Bobbie Molloy.


This size delimiting definition also gets slightly difficult to use when you are studying the microscopic parts of a larger organism, for example the fossilised scales of a fish or a minute example of something that is usually larger like a gastropod (e.g. a snail). Most people studying these topics would consider themselves microvertebrate workers or gastropod workers and not micropalaeontologists. However, many micropalaeontologists, like me also study microscopic remains of larger organisms like fish that they find during laboratory preparations for other microscopic remains.


Biological classification

Some people try to restrict micropalaeontology to particular biological groups that are commonly considered microfossils. This can also be open to personal opinion, for example, palynologists study microscopic organic remains like spores, pollen and oceanic plankton – all microscopic in size – but some of them would consider themselves palynologists rather than micropalaeontologists. The Micropalaeontological Society defines its specialist groups to reflect biological classifications of organisms commonly accepted as microfossil groups.


Age

As with size, there is no agreed age beyond which something stops being recently dead and becomes a fossil. With specimens in this narrow window of age (ie 0-10,000 years old) it is virtually impossible to tell how old a microfossil specimen is without carrying out some sort of destructive chemical analysis on it.


Our collections

At the Museum, we mainly follow the Micropalaeontological Society's definition of a microfossil and in the Palaeontology Department we have collections of Foraminifera, Ostracoda, conodonts, Radiolaria, nannofossils and various palynological groups such as the dinoflagellates and spores. In future posts I will introduce each of these microfossil groups as I highlight projects that are currently happening here at the Museum.


My job is to manage all of these collections which number over 750,000 objects. It would be impossible to count the exact number of specimens because some slides and residues contain hundreds of thousands of specimens.


The lack of clarity over what age makes a microfossil causes problems sometimes with deciding where to store specimens in the Museum collections. In the Palaeontology Department we have all the extant (modern) Foraminifera as well as the fossil specimens, so no problem there. However, ostracods are split between our department and the Zoology Department, with us holding the fossils and Zoology the recent (extant) forms. In practise it is very difficult to draw the line between fossil and recent and we certainly have some ostracods that could be in the Zoology Department and probably vice versa.


The majority of the microfossil collections are Foraminifera, which are unicellular animals with a foramen (i.e. an opening, sometimes multiple) that form small shells of calcium carbonate, silica or organic materials. Examples of Foraminifera are shown below, where the field of view of the slide from the Heron-Allen Collection is about 2cm.


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The Heron-Allen Collection

 

I mentioned that some micropalaeontologists like me also work on microscopic fragments of fish (microvertebrates). At the Museum these are kept with the fish collections so they do not come under my ‘jurisdiction’. However, I still study them and some of my most important discoveries have been on this subject as you will find out in the next post to the blog.



Giles Miller

Giles Miller

Member since: Apr 21, 2010

This is Giles Miller's Curator of Micropalaeontology blog. I make the Museum micropalaeontology collections available to visitors from all over the world, publish articles on the collections, give public talks and occasionally make collections myself.

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