Fieldtrip SE Brazil

Posted on May 30, 2015 by tprg

TPR to the South East of Brazil: Je Landscape Palaeo fieldtrip

Pedra Furada, Sao Joaquim National Park (1890masl), Urubici area

It is not long since I came back from the Jê landscapes Project field trip in the South east of Brazil.

The experience was truly fantastic. I had the pleasure to meet and know incredible landscapes and generous people. As a result we found fantastic sites and collected what we believe are the best representative materials for our project.

Focusing in the vegetational, environmental and climate reconstruction during the existence of the Proto- Jê culture, the aim of the field trip was to collect sediments from bogs at the main three geographical areas where the project is studying the Jê culture: Urubici (Highlands), Rio Fortuna (were the Atlantic forest is) and Campo Belo do Sul (Highlands). Armed with dutch gauge and Russian corer, me and my fantastic assistant Álvaro Costa toured over 200 kilometres within Santa Catarina region looking for deep bañados.

In the Atlantic forest, fundamental piece of the field trip Álvaro Costa next to myself

Our experience in Urubici started very challenging. The very first bog we tried coring was what I would say the most difficult of the whole trip. We simply couldn’t extrude it. It was a clay and silt grey sediments with a large proportion of silica that would stick to the inside of the Russian corer like leeches, and not even using spatulas to do toggle we could extrude them. Long story short, we managed to find a way to extrude without disturbing the sediments and from that moment onward nobody stopped us. We cored 13 sites within the area, all with overlapping and duplicate drives.

Human impact is evident in this Araucaria forest, Urubici area (800masl)

Santa Bárbara peat bog, at 1800masl in the Araucaria forest-Campos (grasslands) boundary

Like black butter. Sediments from Santa Barbara peat bog

Our experience in Rio Fortuna, towards the littoral side of Santa Catarina, was indeed a very different but not an easier landscape to core. To find a bog that didn’t suffer the consequences of agriculture or cattle, or that wasn’t converted in a fish tank to grow trout was the first but not only barrier; being able to cut across with the Russian corer the dry and sandy sediments was another one. We would not give up, and using as much of our patience as well as our weight to push we recovered sediments from four sites very close (~100m) to archaeological finds.

Arrow point found as we were walking by one of the study sites in Rio Fortuna area

Sediments from one of the Rio Fortuna sites (600masl)

Campo Belo do Sul gave us a little truce. Thanks to Frank Mayle, who already went to the area in April 2014 and cored eight fantastic sites, we weren’t in much need to core much more. I personally enjoyed this part of the field by joining to the archaeological team that was in the site excavating Abreu e Garcia (funerary) and Baggio (oversized pit-house) sites. An army of students, plus researchers Dr Mark Robinson, Dr Rafael Corteletti, PI Professor Jose Iriarte, PhD students Jonas Gregorio and Priscila Ulguim and of course, loads of yerba mate there were many hours of tireless digging.

Students working at Abreu e Garcia funerary site, Campo Belo do sul

Another fruitful stop was in Gateados farm, a timber company committed to preserve and protect native vegetation. With the crucial help of Professor Lauri Schorn and his student Alyne Rugiero from University of Blumenau, we collected moss pollsters from the most pristine Araucaria forests available in the area. We will use the pollen rain contained in these natural traps to understand how modern Araucaria forest vegetation expresses in the pollen record.

It was almost two very intense months of travelling, coring and falling, but I would definitely do it again. Now the next step is face the many hours of work in the field translated in sediments to unveil what the past of vegetation and climate was like when Jê culture inhabited these areas.

Almost forgot… I also found mosquitos…

One mosquito bite in my arm, above my wrist… unfortunately not the only one I had

Post by Macarena

@DrMacarenaLC

Fascinating Plants

Posted on May 28, 2015 by tprg

Fascinating result: Fascination of Plants Day

A total success was the outcome of the fascinating international day event co-organised by our laboratory (School of Archaeology, Geography and Environmental Science (SAGES)) and the School of Biological Sciences (SBS) the on 18^th May.

It was a very windy and rainy day, but nothing stopped the team.

The unstoppable Fascination of Plant event team on the day

University staff, undergraduate students, schools with around 130 kids and University of Reading Vice-Chancellor visited the event getting fascinated by the fantastic world of plants.

This was the first time where these two schools worked together to create an event that came alive after Dr Macarena Cárdenas (SAGES)and Dr Jonathan Mitchley (SBS) shared their passion for plants. The result of combining knowledge about the past of plants trough the fossil record and the present modern plants happened to be an enlightening experience for who visited the event.

FoDP_Macarena Cardenas

Dr Macarena Cárdenas fascinating students with microscopic samples of fossil pollen

Dr Jonathan Mitchley un-puzzling students with modern plant material

Keep your senses awake and your eyes on the green as there are plans for more events like this!

For more details and information contact:

Dr Macarena Cárdenas m.l.cardenas@reading.ac.uk

Fascination of Plants

Posted on May 5, 2015 by tprg

The Palaeoecology Research Group in conjunction with the Schools of Biological Sciences is organising a day event to celebrate the third international Fascination of Plants day.

Come and witness the fascination of plants, showcasing a captivating and puzzling plant and its relationship with people past, present and future. Enjoy hands-on activities, guided walks and dramatic historical re-enactment!

Click the image for further details

From Sediment to Slides

Posted on March 13, 2015 by tprg

From Sediment to Slides – phytolith training at the University of Exeter

For the past few weeks I have been lucky enough to have been working in the Archaeology Department at the University of Exeter, where I have been learning how to analyse soil and sediment samples for phytoliths.

In case you are not familiar with them, phytoliths are plant opal silica bodies that are formed from monosilicic acid (H₄SiO₄) taken up by the plant that is then deposited in the cells of the stems, leaves, roots and inflorescences. These silica bodies are formed in different shapes and sizes depending on the type of plant and where in the plant they are produced. In some plant groups, such as Poaceae (grasses), the phytolith characteristics are diagnostic to the sub-family level. You cannot identify these sub-families by analysing pollen grains alone, so phytoliths add another level of detail to palaeo-vegetation reconstructions. Additionally, phytoliths allow you to work at a fine spatial scale because when plants decay the phytoliths are deposited in the soil where the plant lived, so they represent the local vegetation. They also preserve well in aerobic and acidic conditions, so they can be recovered from soils as well as lake sediments.

I spent my first week in Exeter learning how to process soil samples for phytolith analysis with Jenny Watling. From soil to microscope slide it can take about 5 days, depending on the size of your sample. A lot of that time is spent repeatedly washing your sample in the centrifuge after each treatment. Essentially, you need to: (1) remove the clays, (2) remove the carbonates, (3) remove the organics, (4) retrieve the phytoliths by floating them in a heavy liquid, and (5) dry your phytoliths ready for mounting onto a microscope slide.

Picture 1: removal of clays by defloculation

Picture 2: removal of carbonates using HCl

Picture 3: removal of organics using HNO₃

Picture 4: floating the phytoliths in Zn Br₂

Once the slides are ready, you can count the different types of diagnostic phytoliths and draw conclusions about the vegetation that produced them. The key to this is to spend a long time looking at modern reference collection slides to learn what to look out for, and of course having helpful experts on hand to point you in the right direction – thank you Josѐ, Jenny, Sheahan and Lautaro! I spent many hours photographing the extensive reference collection from Dr Josѐ Iriate’s lab to form my own mini digital collection to use when I returned to Reading.

Picture 5: Cyperus sp. Achene body

Picture 6: Heliconia sp. Trough body

Picture 7: Trichomanus sp. Scooped globular body

Picture 8: Erhartoideae scooped bilobate

Picture 9: Panicoideae bilobate

Picture 10: Chloridoideae saddle

All photographs courtesy of Dr Josѐ Iriate, Department of Archeology, University of Exeter
In my final week the really interesting work began as I started to analyse my samples from a lake sediment core taken by Dr John Carson from an ox-bow lake in Acre state, Brazil. My first experience of analysing a real sample slide was quite daunting; it took me almost 5 hours to count 100 phytoliths. Thankfully it turned out I had chosen an unfortunate sample for my first analysis, with a very low concentration of tiny phytoliths, and my second attempt was much more successful; 200 phytoliths in 2 hours.

Picture 11: Image from a slide showing a scooped bilobate (Erhartoideae), a panicoid-type bilobate, a tall saddle (Bambusoideae) and a globular granulate (arboreal indicator)

Picture 12: Image from a slide showing two crosses (Panicoideae) and two echinate globulars (Arecaceae)

I have learnt a lot in my time in Exeter and thoroughly enjoyed it. Now I’m excited to start working on pollen as well…

Heather Plumpton,

PhD student at the University of Reading

Meet Heather:

In my PhD with the Tropical Palaeoecology Research Group at the University of Reading I am interested in looking at ecological patterns over long timescales. I will use palaeoenvironment proxies, such as fossilised pollen and phytoliths, to reconstruct vegetation responses to climatic changes. In particular, I am investigating the long-term impacts of a mid-Holocene (~6000 years ago) drought on ecotonal regions of the Amazon rainforest in northern Bolivia. I am also interested in how plant-climate interactions are represented in Dynamic Global Vegetation Models (DGVMs) and how this feeds into Global Climate Model predictions for future plant responses to climate change.

Fun and field work

Posted on February 1, 2015 by tprg

If you wonder how the life of a Palaeoecologist is in the filed, look below for graphic scenes.

How about this for a tree? Prof Mayle at the Rainforest in Acre, Brazil. Courtesy of Prof F. Mayle

Best transport system for coring equipment, 4×4. In Bolivia. Courtesy of Prof F. Mayle

Proteins are not scarce in the field. Piranha for lunch. John can’t wait to sink his teeth!. Bolivia. Courtesy of Prof F. Mayle

As it was 2,000 years ago, eating Pinhao (Araucaria tree seed) in the field at Santa Catarina State, Brazil. Courtesy of Prof. Mayle

Welcome/Bienvenido/Bem-Vindo!

Posted on October 2, 2014 by tprg

What we do

Our Tropical Palaeoecology Research Group seeks to understand the long-term interactions between climate change, fire, human land use, and vegetation across tropical South America. We do this by using a range of palaeoenvironmental proxies from lake/bog sediments and soils (in particular, pollen, charcoal and phytoliths), and are interested in environmental changes spanning recent millennia, the Holocene, and Quaternary glacial-interglacial cycles. This palaeo perspective can provide important insights into ecosystem resilience/fragility, biogeochemical cycling, and conservation policy, especially in the context of future climate change and human land use. We have a well-equipped tropical palaeoecology laboratory with a modern pollen reference collection of > 2000 species from South American tropical rainforest, dry forest and savanna ecosystems.

Where we do it

Long-term forest-savanna dynamics in Amazonian Bolivia has been the focus of our research for many years, although recent projects have expanded our geographic scope across Brazil – throughout the Amazon basin, the coastal Atlantic Forest, and the southern Brazilian Araucaria (monkey-puzzle) forests.

Who we work with

Because a cross-disciplinary approach is needed to tackle many of our research questions, we have forged close collaborative links with a broad spectrum of scientists, in particular archaeologists and botanists, but also GIS/remote-sensers, modellers, diatomists, and soil scientists/geochemists. We therefore have strong links with a range of institutions, not just across the UK (e.g. Universities of Exeter, Swansea, and Nottingham), but around the world; e.g. University of Utah (USA), Noel Kempff Mercado Natural History Museum (Bolivia) and the Federal University of Para and University of Sao Paulo (Brazil). We are always open for new collaborative opportunities, so please contact us if interested.

Who funds our work

Our recent and ongoing research has been supported by the University of Reading, NERC, AHRC, The Leverhulme Trust, National Geographic, FAPESP (Sao Paulo state, Brazil), and CNPq ‘Science Without Borders’ programme (Brazil).

Members of the group, from left to right: Top: Prof Frank Mayle, Dr John Carson; Bottom: Dr Macarena L. Cárdenas, Dr Joy Singarayer, Heather Plumpton and Richard Smith.