This article demonstrates the stability window of sporopollenin under laboratory simulated diagenetic conditions. We show that sporopollenin is resistant to chemical alteration when subject to low-to-moderate diagenetic conditions, maintaining its original aliphatic:phenolic co-polymer configuration. Under the most extreme of conditions tested here we show that the co-polymer configuration begins to defunctionalise and reploymerise to be replaced in-situ by a predominantly aliphatic polymeric structure, including aliphatic components significantly shorter than originally were present in the starting material. The outcome of this study shows that fossil sporopollenin may still retain its original chemical composition, even after being subjected to diagenesis. Such a finding opens the door for investigating deeper time chemical composition of sporopollenin and environmentally-influenced variations in sporopollenin structure, beyond that currently achieved.
The four fellowships are advertised in four areas of Earth & Environmental Science; however, applications from exceptional scientists in related fields are also welcome.
One of the key goals of the fieldtrip to Ecuador (August-September) was to sample organic and volcanic (tephra) layers from sedimentary exposures with the aim of obtaining new information about past envrionmental change in the region. Our Ecuadorian collaborator, Dr Patricia Mothes (Instituto Geofisico), had identified four of sites she thought might be useful too us: El Fatima Dique, Mera “2” Dique, El Rosol and Vinillos.
At the Fatima site, near Puyo, a thin organic bed was sampled sandwiched between volcanic ash deposits. Wood macrofossils from this deposit have been dated to the last glacial period.
For further descriptions of what we found and field photos read on…
The second part of our Ecuadorian expedition took in lakes and sections close to the towns of Papallacta and Cosanga. The variation in climatic conditions was marked as we experienced first hand the transition from freezing fog and driving rain to burning sun and heat within a few tens of kilometers as we travelled from >4000 m down to around 1000 m elevation.
Sampling the sedimentary section at Vinillos was hampered by a tropical downpour. Sediments recovered from here include volcanic ash, mud slide deposits including large wood macrofossils and fine grained organic sediments probably deposited in still water environments.
Preparing to recover a short core from a pond near the antenas at Cujuca. Short cores will be used for Chironomid analysis.
Tomorrow we will attempt to recover short cores from two more lakes. Then our final few days here in Ecuador will be spent visiting partners and packing up.
The first half of our field work expedition to Ecuador has now been completed. We had a very successful visit to Mera collecting samples from three new sections and recovered short cores from four lakes.
The sediment sections have yielded many wood macrofossils and samples for pollen analysis. It is anticipated that these will shed light on the nature of tropical vegetation during the last glacial period and before. Some of these samples will be analyzed by Hayley as part of her PhD research.
The sedimentary section found near Mera contained layers of crushed forest beneath volcanic ash. These “forest beds” provide a snapshot of vegetation in the landscape at the time of eruption. Part of plants growing on the landscape thousands of years ago are clearly preserved in the sediment.
We have now spent two days in sampling sedimentary sections near the Rio Tigre close to Mera in Ecuador. The sections are peat deposits interspersed with volcanic ash and contain many wood macrofossils. It seems likely that the depositional environment was a shallow water swamp or bog. Although we will have to wait for the analysis of the fossil record to know the composition of the vegetation at the site.
I am writing this August post from the Hotel Rincon Escandinavo (Quito, Ecuador) most of this month has been pretty hectic as we have been preparing for this field work trip and trying to get as many things out the way before hand.
We seem to have been quite involved in conference activity: Lottie presented “500,000 years of vegetation change from West tropical Africa” at the International Paleolimnology Association Symposium in Glasgow, Hayley had an abstract on “Pollen counting for diverse tropical ecosystems” accepted for the Linnean Society Palynology Group meeting (1 November) and group members also submitted abstracts for consideration to be presented at the American Geophysical Union Congress and British Ecological Society meeting (both in December); fingers crossed these will be accepted as well.
Regarding the field work. Preparation seems to have gone well and we have arrived in Quito with all out bags, despite a short (1 hour) connection in Madrid. Tomorrow we will meet up with Dr Patricia Mothes (Instituto Geofisico) and set out our detailed plans. As I have now been up for more than 24 hours I should probably get some sleep… Plan is to blog more about the trip as it happens.
PCRG members taking part in the Milton Keynes NSPCC Half Marathon, 8 July (left to right: Charlotte Miller, Wesley Fraser and William Gosling)
I have been really excited with the increase in the number of posts and various contributions to this blog over the last month or so. So thanks to everyone who has contributed. The excellent content allows me to focus on just a few research and teaching events which have not been previously covered.
1) Welcome to Wesley Fraser who has joined us officilally as a visiting postdoc for a few months. We hope to develop a paper and another grant submission looking at pollen/spore chemistry during this time; for further details see “Do plants wear sunblock” post.
2) Well done to Frazer and Hayley for performing well in their end of year 1 mini-vivas. Both projects are progressing well and we are all looking forward to field work at the end of the month. Hopefully most of the prepartation and equipment are now in place…
3) Potential for more exiting collaborations was also developed at two meetings. The first, at the Natural History Museum and, in conjunction with long term collaborator Steve Brooks was with old friends Mick Frogley (Sussex) and Alex Chepstow-Lusty. Both Mick and Alex taught me when I was at Cambridge and it would be super exiting to develop a new collaboration with them looking at Chironomids in Andean lakes. The second was at the Univesity of Nottingham as I took part in a UK Tropical Peatlands meeting which brought together ecologists and palaeoecologists from Nottingham, Leeds, Leicester and The OU. The aim of the meeting was to coordinate papers and grant applications.
4) At the end of July beginning of August I taught on the “Sedimentary Rocks and Fossils in the field” topic for the new Practical Science, Earth & Environment (SXG288) module which The OU now offers. Longridge Towers School (no children around this time of year) provided the perfect base for investigating the sedimentary geology of the region. The small group of students had the opportunity to make field observations and test hypotheses related to past environmental change. Everyone was very excited to find numerous fossils and interesting sedimentary structres and had fun trying to work out what they all meant! Congratulations to Angela Coe for putting together this great event.
Ecology of the past 