Colorado Rocks! Attending a research meeting on sedimentary systems

By Lucy Clarke (@DrLucyClarke)

  

Continuing the blog series looking at what we have been getting up to this summer...

Last week I was lucky enough to be in the US for a research conference and I'm sharing my experiences of this with you in this blog post. This was a specialist meeting, with about 50 people attending, focusing on the “Autogenic Dynamics of Sedimentary Systems” – so basically the importance of internal processes (i.e autogenic processes) in driving change in natural systems and how this is recorded in the 'rock record'.

You may be asking yourself... why is it important to understand what's recorded in the rock record? Well, geologists use this information to reconstruct long term environmental change. Layers of material are laid down through time and over lengthy time periods these form the rocks that we see all around us (i.e. a sedimentary system). By examining the grain size, composition and structures in these rocks it can tell us information about the type of processes that formed them and what the climate was like at the time using a technique called stratigraphy. So it's important to know not only how things like climate and tectonics can influence the sediment build up and preservation as it turns to rock, but also what effect other internal processes can have on this so that a correct interpretation can be made.

Stratigraphic profile from Colorado National Monument showing a fluvial section with thick layers of floodplain with thinner, coarser bands of channel material in between

The aim of the meeting was to bring together an interdisciplinary group of researchers from ecology, geochemistry, geography, geology, and palaeontology to look at the research advances that have been made in different sedimentary systems to evaluate what, if any, ‘autogenic’ signals can be determined. Presentations covered a range of topics and included field, numerical modelling and experimental approaches that were being used to try and tackle this problem.

I presented the research that I introduced in my blog on 28 August 2013: What drives change on alluvial fans? I talked about how my experiments showed that internal processes within these landforms caused observable changes in the flow patterns. 

The sessions were really interesting and thought provoking. It was designed to be a discussion rather than just a one-way presentation of information from the speakers, consequently we had lots of time for asking questions supplemented by break out groups to follow up on ideas and think about the 'bigger picture'. I found this particularly useful as it helped me to generate new ideas as to how to develop my own research, as well as starting to think about the wider implications of my research. Additionally having the opportunity to talk to people from other related, but slightly different disciplines, has certainly broadened my perspectives.

Looking over the Colorado River to the city of Grand Junction (to the left) and the Grand Junction Main Street (to the right)

The meeting was held in the city of Grand Junction - situated in central Colorado, the town sits on the Colorado River with lots of wineries and agricultural land surrounding it. Grand Junction is a small traditional mid-West town with a population of about 60,000 that boasts a university and a quaint main street that has a night market every Thursday evening during the summer. Temperatures were around 30°C every day and despite a couple of thunderstorms at the start of my trip the weather was great. Close to the town is the Colorado National Monument, this is a national park about 85 km² in size, containing stunning mesas and canyons. As part of the conference we were treated to a field day to experience the park's impressive geologic formations and see if we could explore, and apply, some of the conference themes in a field setting.

Colorado National Monument: looking over the national park (left) and geologists looking at a rock section showing preserved sand dunes (right)

I thoroughly enjoyed my week in Colorado. I got to explore a new area but most of all I made new connections for my research with the potential for new collaborations in the future. I learned about lots of current research from different, but related, areas that I hadn’t previously been aware of, which has rejuvenated my own research in this area - so all round it was a successful trip!

Enjoying the sunshine on the field day in Colorado National Monument

Happy Birthday BES!

Celebrating 100 years of the British Ecological Society
By Dr Lindsey Atkinson (@LJA_1)

This year the British Ecological Society is 100 years old. It is the oldest ecological society in the world and its aims are ‘to advance ecology and make it count‘.  To mark the occasion there have been a series of events celebrating ecological science and research and promoting public engagement through the Festival of Ecology.  The celebrations also included a major international conference: ‘Ecology: into the next 100 years’.  

This was the 11^th International Congress of the International Association for Ecology (INTECOL 2013) bringing together about 2000 ecologists from around the world (including myself and two GEES colleagues) to give 1000 talks and present over 500 posters.

So why are we talking about an ecology conference on GEESology?  One thing that came across at this conference was the sheer diversity of the topics covered by the broad umbrella of ecology.  The themes ranged across theoretical and applied ecology, conservation management and public policy.  Specific topics included sustainable agriculture, sustainable cities, biodiversity, ecosystem function, biogeography, climate change ecology and public policy, poverty alleviation and much more, linking in to many of the interests of GEESologists.

In the introductory session Professor Georgina Mace, President of the BES, welcomed the delegates in the Capital Auditorium of the ICC London ExCel Centre (last year the venue for the Olympic boxing, wrestling and fencing).  She was followed by the President of Intecol, Professor Alan Covitch, who outlined challenges for ecologists for the next 100 years emphasizing the vital role of communication between disciplines.  Finally, Professor Ilkka Hanski of the International Scientific Committee of the Congress emphasized the need for ‘solid ecological knowledge’ to inform ‘well-educated decision makers’.

The conference then got under way with an excellent first plenary lecture given by Professor Sandra Diaz of Cordoba National University in Argentina.  Professor Diaz discussed using a plant functional trait approach to describe patterns of diversity at a global scale.  The aim is to provide a framework for predicting the response of ecosystems to environmental change and the impact that this will have on the services those ecosystems provide.   Another highlight of the conference was Professor Mace’s Presidential Address ‘Looking forwards not backwards: biodiversity conservation in the 21^st Century’ – you can read a summary of her talk on the BES blog.

The Sex & Bugs & Rock 'n Roll Roadshow has been touring
 music festivals this year to tell people about ecology

The opportunity for everyone to get involved in ecology was highlighted during the week through sessions about 'citizen science'.  No need to be an expert as the information you will need is provided, often via the internet or an ‘app’.  The data contributions are validated and interpreted by scientists.  Examples include the Treezilla project which aims to map all the trees in the UK and shows how they benefit the local environment and Conker Tree Science, mapping the spread of an invasive moth which is damaging our horse chestnut trees. There are citizen science projects monitoring birds, pollinators, ponds and hedgerows and many others – perhaps there’s one to spark your interest!

Over the next few days we listened to more plenary talks from leading scientists as well as talks by scientists at all levels from graduate students to emeritus professors, participated in workshops, discussed our posters, caught up with old friends and met new people.  Even with the help of the ‘app’ to negotiate the programme it wasn’t possible to go to everything of interest.  At times it felt a little too busy with so much going on but the advantage of going to such a broad-ranging conference is being able to dip into other sessions to learn something about a new topic area and making connections with colleagues in other disciplines.  We went home tired but inspired to explore new work directions!

Palynology: why pollen is not to be sniffed at!

by Michelle Farrell (@DrM_Farrell)

To around 20% of the UK population, pollen is familiar as the cause of hay fever during the spring and summer months. To a very small minority (ironically, many of them well acquainted with the runny-nosed, itchy-eyed symptoms of hay fever themselves), pollen is much more than an allergen. Pollen grains contain the male gametophyte of seed-producing plants, and in order to increase their chances of reproductive success, wind-pollinated plants produce pollen in vast quantities. The small size of pollen grains (generally in the order of 20 to 40 microns, a micron being one thousandth of a millimetre) means that when they are released by a plant they become widely dispersed in the environment. As the plant has no control over where its pollen grains end up, another part of the reproductive strategy is that the grains have a very tough outer casing or exine, made of a substance called sporopollenin, allowing them to survive in less than perfect conditions. This outer wall can be preserved in several environments, particularly waterlogged ones, for tens of thousands of years. This combination of pollen being produced in large quantities, wide dispersal in the environment, excellent preservation under the right conditions, and the fact that pollen grains can often be identified to family, genus and even species level, is what makes them such a valuable tool for research.  

Coring to retrieve pollen-bearing sediments from a bog
on Orkney, Scotland

Pollen analysis is one of the most common methods used for investigating past environments. Pollen is often preserved in waterlogged environments where sediments accumulate, such as lakes and peat bogs. Cores of sediment can be extracted from these locations, and sub-samples from various depths are then subjected to a series of physical and chemical laboratory treatments which remove the majority of the inorganic sediments and large organic debris, leaving behind the fine organic fraction of the sediment. It is this fraction that contains the pollen grains, as well as other tiny organic remains including fern and fungal spores, other fungal remains such as hyphae, and fragments of charcoal from either natural or anthropogenic fires. The study of all these remains together is known as palynology, a term coined by the British scientists Hyde and Williams in 1944 and derived from Greek words meaning ‘the study of small particles sprinkled about’.


The stripes in this core segment indicate that the sediments
were deposited under different environmental conditions

Once you have concentrated the fine organic fraction of the sediment, the next stage is to identify the botanical remains contained within it. Much as a botanist would use a key to help them to identify plants out in the field, palynologists use keys to pollen and spores to aid their identification of specimens under the microscope in the lab. The identification and study of fungal remains is still a relatively new technique, and to date no definitive key to these types of remains has been published. Therefore I’ll focus here on the distinctive characteristics of pollen grains that allow palynologists to distinguish between the different taxa present in a sample. One of the most distinctive features of pollen grains is their apertures. There are two types of aperture: pori (pores), roughly spherical in shape, and colpi (furrows), which are elongated and have pointed ends. Some grains have both colpi and pori in the same apertures, and are known as colporate. The number and arrangement of the apertures is also key in pollen identification. The number of apertures is indicated by the use of the prefixes mono-, di-, tri-, tetra-, penta- and hexa- before the terms porate, colpate and colporate. The prefix poly- is used to denote the presence of more than six apertures. Usually the apertures are arranged equidistantly around the equator of the pollen grain, and this is indicated by the prefix zono-. Panto- is used when the apertures are scattered all over the surface of the grain. Some examples of the way in which apertures are used to identify pollen grains are shown below.



Betula (birch) pollen: trizonoporate,
with three pores arranged equidistantly
 around the equator of the grain

Fraxinus excelsior (common ash) pollen:
trizonocolpate, with three furrows arranged
equidistantly around the equator of the grain



Rumex obtusifolius (broad-leaved dock):
tetrazonocolporate, with four apertures
made up of both colpi and pori

Plantago lanceolata (ribwort plantain):
polypantoporate, with many pores scattered
all over the surface of the grain

The pattern of sculpturing found on the surface of the exine is another crucial factor in the identification of pollen grains. Around fifteen different surface patterns have been described, and two of the more distinctive patterns are shown in the images below.


Cirsium arvense (creeping thistle) pollen, a
good example of echinate surface sculpture



Ulmus (elm) pollen, displaying rugulate
surface sculpturing

Size can also be important in distinguishing between pollen taxa, particularly members of the grass family. The two images below show the difference in size between a wild grass, Phragmites australis (common reed) and a cultivated grass, Triticum aestivum (wheat).


Phragmites australis (common reed) pollen

Triticum aestivum (wheat) pollen








The identification and recording of pollen grains from different depths within a sediment core can be used to provide information on how the vegetation surrounding the core site has changed over time. Sediment cores can often be accurately dated using radiocarbon, allowing the changes in environment to be tied to a chronology. Palynology has great potential for providing baseline data for the development of conservation management strategies, and is also useful from an ecological perspective as it can give insights into how plant communities have responded to climate change in the past, thereby allowing predictions to be made about how vegetation and ecosystems may be affected by future climate change.

One of my main research interests is in the use of palynology as a tool to unpick the ways in which humans interacted with their environments during the Holocene (the period since the end of the last ice age, approximately 11,500 years ago, until the present day). I intend to write more about the archaeological applications of palynology in future posts, but as a taster, it is possible to determine when people began farming in an area, what crops they were growing, where they grazed their animals, whether they cleared woodland to create more land for agriculture, and how they contributed to the development of cultural landscapes such as heathlands. It is also possible to investigate the ways in which people may have managed their environments and responded to climate change in the past, for example managing heathland by deliberate burning in order to maintain the quality of grazing. It may even be possible to detect woodland management practices such as coppicing, and Jane Bunting will write about her work on this in the next GEES-ology post.