Tuesday, 31 May 2016

More on our project investigating human impact on Malaysian wetlands...this time by Masters student Charly Briddon

Charly Briddon on Tasik Chini undertaking a diatom habitat
survey.
Hi, my name is Charly Briddon and I am Keele University student currently undertaking research for my MSc in Geoscience. For my international placement I have joined a collaborative project within the Centre for Environmental Geochemistry (a collaboration between the University of Nottingham and the British Geological Survey) involving supervisors at Keele University (Dr Antonia Law), University of Nottingham (Dr Suzanne McGowan) and the British Geological Survey (Dr Keely Mills). This has given me the opportunity to spend six months at the University of Nottingham Campus in Malaysia investigating how human activities within the lake catchment of a really special wetland system (Tasik Chini) has changed the lake ecology over time…

The diverse plant communities of Tasik Chini provide a range
of different habitats for microscopic diatoms. 
The Tasik Chini research project has been introduced in previous blogs by Prof Melanie Leng and Dr Stefan Engels. My role in the project is to primarily use diatoms to reconstruct past conditions in the lake over the past hundred years or so.  I have been analysing sediment cores collected from the various basins in the lake during the summer of 2015.  Fossil diatoms (types of algae with silica shells) can provide information about water quality, water level change and shifts in lake habitat structure. However, there is not a lot of previous diatom work on these types of shallow tropical wetlands and so I am supplementing this work by investigating where the diatoms are growing today. In April 2016 I collected diatom samples from plants, muds and waters in the lake to determine whether there are habitat affinities that I can use to interpret the core data.

The second part of my project is to try to characterise the organic material in the lake sediments. I started off by conducting loss-on-ignition analysis, which is literally burning the mud to give an estimate of the proportion of organic versus minerogenic material. I am also developing a technique to look at the fluorescence characteristics of the porewaters. We are using a UV visible spectrometer which provides 3-dimensional data on excitation and emission to provide information on where the organic matter in the sediments comes from- for example is it from soil erosion or from algal blooms in the lake.  This technique is quite novel and I am looking forward to using this piece of equipment which is brand new to the university, this part of my project is being supervised by Dr Shafi Tareq from the School of Biosciences in Malaysia.
Charly Briddon, Shafi Tareq and Suzanne McGowan
undertaking porewater flourescence analysis. 

Initial results from the diatom and organic analysis indicate that changes observed in the sediments appear to correspond with changes in human activities in the lake catchment, possibly associated with deforestation in the 1940s and the building of the dam around 1995. We also think that there might be evidence for acidification from atmospheric contamination in recent decades. However, we are waiting for dating of the core to be completed before these results can be interpreted with more certainty. I am looking forward to completing my laboratory work in mid-June when analysis of the results obtained and write up of my dissertation can start in earnest.

Charly Briddon is a Masters student at Keele University undertaking her project within the Centre for Environmental Geochemistry at the University of Nottingham and the British Geological Survey 







Friday, 20 May 2016

Reconstructing the pollution history of southeast Asian wetlands...by Stefan Engels

Stefan with field assistant Charlotte (MRes student
from Keele University) collecting plant samples.
How time flies! It has only been about 4 months since I started my new job as a research fellow with  Melanie Leng and Suzanne McGowan within the Centre for Environmental Geochemistry. The main aim of my research project is to reconstruct the pollution history of southeast Asian wetland systems, and one of the first locations that we selected as a study-site was Tasik Chini on the Malaysian peninsula, here I tell you about progress to date... 

Preliminary laboratory data obtained from short sediment cores that had been previously collected shows the first evidence of recent ecosystem change. To be able to study this in more detail, and to ensure that we have samples that predate the recent period of extensive human impact on the environment, we decided to revisit Tasik Chini this spring with the main goal of collecting longer sediment cores, hopefully dating back several thousands of years. I say ‘hopefully dating back’, as scientific data on this tropical wetland ecosystem is extremely sparse. We basically don’t know when or why it formed, nor did we know how long the sedimentary record goes back in time. Therefore, this project will yield a lot of surprises!

Suzanne showing some of the core sediments we collected from Tasik Chini.
On the 18th April I flew to Kuala Lumpur where I am met with Suzanne McGowan and Ginnie Pannizo (both University of Nottingham). We participated in a local workshop in Kuala Lumper on projects across SE Asia, followed by a great evening lecture by Professor David Taylor (National University of Singapore) on geostatistics, insect-borne diseases and climate change. A truly interdisciplinary topic! We then drove east to the more rural area of Pahang. On the 4-hr long drive I couldn’t help but marvel at the scale of impact that the Malaysian economy has had on the landscape: we basically don’t see anything but oil palm plantations. 

The core sediments have arrived
safely back in the UK!
Taking wetland core sediments in the tropics turns out not to be unlike coring in the subarctic, which is where I’ve done most of my previous fieldwork. One noticeable difference is the coring equipment: whereas the metal extension rods can freeze together in the subarctic, in Malaysia they get so hot that they left some of our field crew with some serious blisters! I was also kept awake by geckos that were “chatting” in my room all night (not something that happens in the subarctic). The trip was very successful though, we managed to collect long sediment cores from a number of locations across the wetland. I am now back in the UK and are subjecting these cores to a range of different laboratory-based analyses, ranging from classic measurements of the amount of carbon to modern molecular approaches where we can find out where the carbon came from (agriculture, mining, sewage). While the results of the project will take some time to become available, the memories of doing fieldwork in an area that is full of monkeys, monitor lizards and geckos will remain with me for quite a while.


Stefan Engels is a Research Fellow within the Centre for Environmental Geochemistry (University of Nottingham and British Geological Survey).  








Monday, 16 May 2016

Are land-use decisions by African elephants influenced by environmental geochemistry?...by Michael Watts, Lisa Yon and Stephen Cunningham

Background

This is a unique, interdisciplinary project involving environmental geochemistry, plant science, and animal health between a range of partners, including BGS and the University of Nottingham (UoN) to address research questions which have important and practical implications for wildlife health and conservation. In the first phase of the project, mineral levels in a range of biological samples (serum, hair, nails) from elephants at five UK zoos will be measured to validate their use as possible biomarkers of mineral status in wild elephants. The mineral content of food, soil and water consumed by these elephants will be determined.

The second phase of this project will apply these validated methods to a study of wild African elephants. The multi–element capability of ICP–MS for measuring environmental/biomonitoring samples enables an estimation of mineral balance and potential metal uptake. The working hypothesis is that the elephants in this study group are deficient in phosphorus, owing to a deficiency in the (soil and) forage in a South African National Park. This drives the elephants to supplement their phosphorus from the water, soil and forage on land surrounding a phosphate mine in close proximity to the National Park. Elephant incursion into nearby human settlements has resulted in human–elephant conflict, causing risk of injury and lost income. This project may identify key locations in the elephants’ home range where mineral–supplemented forage, or mineral licks, may be placed to reduce the drive to seek additional sources of phosphorus; this could reduce human–elephant conflict. This project provides opportunities for varied work: fieldwork in UK Zoos and South Africa for environmental/biomonitoring analyses of wild elephants, specialist laboratory and data interpretation training at BGS and UoN and translation into advice to relevant stakeholders.


Funding

This work will be focussed on a PhD project from the NERC Envision Doctoral Training Programme, with additional support from the Hermes Trust and Royal Society International Exchange scheme. The project is based on a Centre for Environmental Geochemistry collaboration between the Inorganic Geochemistry (Dr Michael Watts) and Stable Isotopes teams (Professor Melanie Leng) at BGS and Schools of Veterinary (Dr Lisa Yon) and Biosciences (Professor Martin Broadley) at the University of Nottingham. The collaboration is further strengthened by partners in five UK zoos and with partners in South Africa who have been studying elephant populations there for the past two decades, tracking elephant movements using GPS and GMS to better understand their habitat use.

Sample collection 

Recently, in April, the first sample collection was undertaken at Knowsley Safari Park, whose keepers were extremely interested in the possibilities of the project.  The keepers enthusiastically shared their immense knowledge on the measures they undertake to ensure the welfare of their elephants, the individual elephant dietary intakes and idiosyncrasies of each elephant.  We initially started with an evaluation of food and water intake through sample collections; these samples will be measured for ‘essential’ mineral content (e.g. zinc, iron) to determine dietary intakes and possible seasonal changes in forage and hay over the next 12 months.  These data will be related to mineral measurements in the elephants’ toenails, plasma, tail hair and faeces to validate methodologies for use and comparison with wild elephants.

Images from L-R: Elephant toe nail trimmings; tail hair clipping; Knowsley elephant team (Front row L-R (green shirts):
 Stephen Cunningham, Alex Spooner, Andy Doyle, Libby Ward. Back row L-R: Aurelie Devez, Michael Watts,
Daniel Middleton, Lisa Yon)
We would like to thank Stephen Cunningham and his team at Knowsley Safari Park for their enthusiasm and collaboration, particularly as part of the launch of the project and helping us to improve our planned methodology for sample collection and interpretation of data as the project proceeds.

For further information:
mwatts@bgs.ac.uk and lisa.yon@nottingham.ac.uk

More information will follow at:
http://www.environmentalgeochemistry.org/research/BiochemicalCycling.html 
https://www.knowsleysafariexperience.co.uk/ 
@KnowsleySafari, facebook.com/knowsleysafari 

Thursday, 12 May 2016

Bugs in soil prefer a good spread of food...by Barry Rawlins


Barry and the synchrotron
On my way to work I cycle past a field of grazing cows which is next to a milking parlour. A while ago I stopped to ask the friendly farmer, "Can I have a bit of the soil from your field?”

"Yes”, he replied, “but what do you want it for?"

I almost sighed. I knew if I had to explain thoroughly why I wanted it, my answer would be long and complicated. "Well, I want to do an experiment where I take lumps of your soil to a lead-lined room in Oxfordshire and shine light onto it that is 10 billion times brighter than the sun."

He looked over at his colleague with a confused expression, as if to say, we've got a right one here. But he did let me take some of his soil.

So, why did I need these lumps of soil? I want to understand what might help or prevent bugs (bacteria) in the soil eating their source of food – carbon. When bugs eat the carbon it is released to the air as carbon dioxide, the main greenhouse gas. If we understand this process better, we might be able to store more carbon in the soil and slow down climate change.

 A slice through a soil aggregate showing the
position of organic matter, minerals and pores.
Bugs in soil live in the pore spaces – the air- and water-filled gaps between the solid bits. The food which bugs want to eat – the carbon – is unevenly spread throughout each lump, which we soil scientists call ‘aggregates’. Sometimes carbon occurs as big clumps in only a few places in an aggregate, whilst in other aggregates the carbon occurs more frequently as lots of small pieces. The question I wanted to answer in my experiment was: in which of these two cases do the bugs eat more carbon?

A novel way to answer this was to do three things: first, measure how well the bugs fed on carbon in many soil aggregates in the laboratory; second, stain the carbon in these aggregates using a chemical, and finally put the stained aggregates of soil into a bright light source called a synchrotron. The synchrotron shows us in three dimensions the location of the stained carbon inside the aggregates. It also shows us the location of the pore spaces.

(When I was explaining this to the friendly farmer to make it sound exciting I said, "No one has done this before!" He still didn't look convinced.)

After the experiment I compared the amount of carbon the bugs had eaten with how it was spread out inside each aggregate. I found that the bugs had eaten more of the carbon when it was distributed more frequently, more pieces throughout the aggregate. I need to analyse more aggregates to have greater confidence in this finding, so I will have to visit some more friendly farmers and hope I can convince them to give me some lumps of their soil. I am expecting to see more confused expressions.

The research I describe above was a collaboration of several BGS scientists and other colleagues at the Diamond Light Source campus in Harwell. We wrote this paper and there is a movie on the BGS YouTube channel that shows me talking about the experiment at the synchrotron.

Friday, 6 May 2016

Investigating Climate Change in Eastern Australia...by Melanie Leng

Melanie Leng is the head of the Stable Isotope Facility
at the British Geological Survey
In the stable Isotope Facility at the British Geological survey we spend most of our time collaborating with UK universities and research institutes. However, every now and again we get an opportunity that’s too good to be true… One such opportunity came a few of years ago when an email popped into my inbox from Australia. Dr John Tibby and Dr Cameron Barr (from the University of Adelaide) explained that in Australia they have a particular problem in that there are relatively few geological archives of climate change, so researchers into past climate tend to rely on short timescale corals (which can be related to seawater salinity and temperatures) or tree rings (a proxy for rainfall amount). However, both corals and trees tend to only live for a few hundred years, so they were keen to develop new records of Australian climate… 

Cameron Barr sampling leaves from the
paperbark tree on Fraser Island, Queensland
John and Cam hypothesised that the broad-leaved paperbark tree (Melaleuca quinquenervia for those botanically minded) might contain a signal of the amount of rainfall as it’s long been known that the geochemistry (specifically the carbon isotope composition which could be measured within the Stable Isotope Facility at the BGS) of some leaves change in response to water stress. The drier the climate the less the leaves evapotranspirate (similar to sweating), meaning that the “pores” on a leaf are more closed and restrict the plant’s ability to use CO2 from the atmosphere. When conditions are wet, the pores open and the plants can use more CO2 from the atmopshere. This difference in the carbon utilised is ultimately recorded in the leaf carbon as the leaves grow under different climate conditions. With this relationship in mind, we sampled paperbark tree leaves, experimenting with leaves from different parts of the tree, as well as obtaining leaves that had been collected over an eleven year period. We sampled the leaves and compared the carbon to the amount of rainfall for each year, which on North Stradbroke Island SE Queensland, was directly related to water levels and therefore how wet the years were.
One of the lakes on North Stradbroke Island surrounded
by paperbark trees

Overall, we have shown that there is a significant relationship between the leaf carbon and rainfall (averaged over the life span of the leaf). This finding will now allow us to collect much longer records of climate in Australia because we looked in the lakes of Fraser and North Stradbroke Islands which have paperbark trees growing on their shores and found that their leaves were preserved in some of the lake sediments. The leaves we have collected go back thousands of years, and thus we now will be able to investigate aridity in Eastern Australia as well as other places where these trees grow, such as Papua New Guinea and New Caledonia, so there is more to come!

Our paper detailing these initial findings has recently been published, please see: Tibby, J., Barr, C., McInerney, F.A., Henderson, A.C.G., Leng, M.J., Greenway, M., Marshall, J.C., McGregor, G.B., Tyler, J.J., McNeil, V. 2016. Carbon isotope discrimination in leaves of the broad-leaved paperbark tree, Melaleuca quinquenervia, as a tool for quantifying past tropical and subtropical rainfall. Global Change Biology
A core of sediment from the lake showing a sand layer (white)
from an erosion event, and fragments of paperbark tree leaves
 within the lake sediment mud which has accumulated over
thousands of years


Thanks go to all our collaborators (co-authors), but special thanks go to Margaret Greenway from Griffith University who collected leaves every 28 days (even on Boxing Day!) for more than 12 years

Melanie Leng is the head of the Stable Isotope Facility at the British Geological Survey, Twitter @MelJLeng.