Tuesday, 21 October 2014

Caves and Climate Change…. by Andi Smith

As we strive to understand modern day climate change and the possible impact humans are having on our environment, many scientists look to the past to provide evidence of natural climate evolution. Andrew Smith is one such scientist. Here he shares how analysing Spanish stalagmites has helped unlock the last 12,500 years of climatic changes as well as large scale rainfall dynamics throughout Europe...
So why caves?
Records of climate change can often be extracted from sediments, which have built up under different conditions to those we see today. Traditionally ice, ocean and lake cores have been the main areas of investigation, but it is now becoming increasingly common to use cave stalagmites to collect evidence of environmental change.

The formation of stalagmites
Here I am with some fine speleothem formations
in Shuttleworth Pot, Yorkshire, UK.
Cave formations or ‘speleothems’ are carbonate deposits that are gradually laid down by the deposition of limestone from cave drip waters. These waters originate as rainfall and enter the cave via the soil zone and then by exploiting existing bedrock fractures, further dissolving the surrounding limestone. As water enters the cave chamber it deposits it’s dissolved limestone load, creating stalactites that hang from the ceiling and stalagmites, which develop upwards from the floor.
Importantly, stalagmites develop year on year and whilst doing so incorporate the chemical signature of the water from which they have precipitated. Speleothems therefore encapsulate a wealth of chemical information, which can be used to provide evidence of changing rainfall patterns, vegetation productivity and regional aridity. In this current study, two stalagmites were extracted from a small cave in northern Spain. These speleothem indicate significant variations in rainfall during the last 12,500 years; offering an important record of environmental change, which may help us understand the development of human populations in this region.
Does the rain in Spain really fall on the plain?
Well…. honestly I’m not sure. However by analysing oxygen isotopes in the speleothem (a nice introduction to isotopes is provided in a previous blog post by BGS postdoctoral researcher J. Dean) we can assess how the amount of rainfall received in N. Spain has changed during the Holocene. A greater proportion of the lighter oxygen isotope (16O) in the record is driven by intense rainfall, whilst more of the heavier 18O can be attributed to lower rainfall amounts and enhanced evaporation. 
Automated drilling of the stalagmite creates a carbonate
powder which is then analysed for oxygen isotopes
Using the isotopic ratio we can identify periods of enhanced rainfall and extreme aridity during the Holocene. Our stalagmites indicate semi-glacial, arid conditions in the Younger Dryas (12,500 years BP), which rapidly subsided leading to very wet conditions by 8,500 BP. This change in rainfall is hugely important as it marks the start of the Holocene, a period of favourable climatic conditions which have supported rapid human development across the globe.
However, the Holocene has not always been climatically favourable. We identify a period of extreme aridity in N. Spain between 6000 and 4800 years BP, coinciding with the desertification of central Africa. It is around this time that human populations engaged in sedimentary farming activities in N. Spain, possibly related to the growing environmental pressures experienced during periods of drought. The latter part of the Holocene has been dominated by fluctuations in rainfall delivery and importantly, we identify dry climatic conditions around the timing of the Medieval Climate Anomaly and wetter conditions during the Little Ice Age, possibly related to variations in solar activity.
Whilst the speleothem records identify variations in rainfall amount at discrete time periods, it also becomes clear that Holocene rainfall dynamics have been influenced by a natural underlying climate cycle, with a periodicity of 1500 years.
Modern day environmental conditions near to the cave site in N. Spain

The 1500 year cycle in Europe’s climate
There has been great debate in the scientific community about the possible existence of an underlying (1500 year) cycle in European climate records, since the identification of such a cycle in Atlantic Ocean cores by Bond et al., (1997). This has sparked further investigation, centring on the forcing mechanisms that maybe capable of driving such a dominant climate cycle.

Our speleothem records provide further evidence to support this 1500 year cycle and are closely linked to the ocean core records of Bond. This close coupling indicates a singular control over both ocean circulation patterns and the delivery of rainfall to southern Europe. We identify that the North Atlantic Oscillation (NAO) has the capacity to influence both atmospheric and oceanic systems simultaneously. Our speleothem records therefore substantially add to the debate surrounding millennial scale cycles in Holocene climate and offer a coherent solution as to what forces such large scale cycles in European climate records.


Andi is a recently completed PhD student at Lancaster University and the BGS. Andi was supervised at Lancaster by Dr Peter Wynn and Prof Philip Barker, and at the BGS by Prof Melanie Leng and Dr Steve Noble. His thesis was entitled Speleothem Climate Capture – A Holocene Reconstruction of Northern Iberian Climate and Environmental Change.

Monday, 20 October 2014

Printed Mountains... by Phil Tarr

Here's a little blog about Phil and how he combined his IT wizardry & ingenuity with our data to make 3D printed geological models. If you also want to write a blog about how you're using our data in a novel mash up please get in touch via the 'Contribute' tab above...

Hi, I'm Phil Tarr, I'm not a geologist but I have an interest in everything to do with mountains, and rocks are what mountains are made of! I am a retired telecommunications engineer and more recently a retired academic who taught Computer Science at Goldsmiths, University of London. 

Back in 2013 I spent six months immobilised and largely confined to my home with a ruptured Achilles' tendon. I decided to use this time to start a new hobby: making 3D models of mountains. I have always wanted to make models of mountains, but lacked both the skill and patience to work with papier mâché which seemed to be the only medium available to me.   Having read about 3D printing I then realised that I could develop 3D mountain models just using my IT skills. But I knew nothing about the software applications that I would need to use.

Scafell Pike: 3km x 6km which, at a 1:50,000 scale,
is a model 6cm x 12cm in size
I decided to go ahead and taught myself (with help from a 3D designer in the US) how to use 3D design software to process elevation data (Ordnance Survey Terrain 50 OpenData). I soon realised that a large model or a completely solid model would be very expensive to print, so I had to learn how to produce a hollow model. This was not an easy task, as it meant that I had to thicken the upper surface of the model to exactly 2mm.

I wanted the sides of the model to be precisely aligned to the national grid, but the elevation data was sampled in the centre of 50m squares and not at the edges of these squares, so I had to learn how to slice through the data to interpolate the elevations along the walls of the model. For some reason, doing this created holes in the surface mesh, which I then had to learn how to re-stitch. In the interest of accuracy, I also decided not to exaggerate the vertical scale which would make the model look more dramatic.

Snowdon: 6km x 3km which, at a 1:50,000 scale,
is a model 12cm x 6cm in size
I added some text to the side of the models and a grid, a compass rose, a copyright notice and the name, position and height of the main peaks on the underside of the model. I hoped that there might be a market for these models and that, though sales, I could fund the development of further models.

When I showed some of the prototype models to my cousin, an ex-geography teacher with an interest in geology, he suggested that a geological map would also look good draped over the model. I set up a Value Added Retailer Agreement with the BGS to supply me with DiGMapGB-50 data for just three mountains (Ben Nevis, Scafell Pike and Snowdon) as I felt that it would be too risky to spend any more on images when I did not know how many models I could sell.

Ben Nevis: 3km x 6km which, at a 1:50,000 scale,
is a model 6cm x 12cm in size
I have now completed all three models and they can be purchased from my web shop on Shapeways. You can keep up to date with my plans to develop my models by following @MountainShapes on Twitter.  

If you have any ideas, queries or comments about my models, please feel free to contact me via phil@mountainshapes.com


Wednesday, 15 October 2014

Ghosts, ghouls and disappearing pools...By Kirstin Lemon

The remote upland lake of Loughareema in Co. Antrim is known to most people in Northern Ireland as the vanishing lake. Its bleak and isolated location means that it is frequently shrouded in fog, and coupled with the fact that it is surrounded by bleak blanket bog means that it is not the most inviting place to stop for a picnic.

View of empty Loughareema
To most people, Loughareema is best known for its ghost stories. Local legend tells us of the drowning of a coach and horses in the 19th century as they tried to cross the lake when it was full. Bizarrely, a road had been built through the lake when it was empty so in the dead of night it was impossible to tell if water levels were high or low. It is said that on nights when the lake is full, a phantom ghost haunts the shoreline, and together with the prospect of the sight of a kelpie, or water-ghoul, Loughareema is not short of a story.

To scientists, Loughareema is regarded as one of Northern Ireland's most enigmatic geological sites. This ephemeral or temporary lake lives up to its title as the vanishing lake as it may be empty of water one day and be completely full the next. 

The mechanism for drainage at Loughareema has baffled scientists for years, adding to the mystery of the site, but all of that is about to change. Dr Paul Wilson, an expert in the distribution and movement of water within rocks with the British Geological Survey, has recently embarked on a detailed study of Loughareema. He explains more:

Same view of Loughareema with high water
"Loughareema is a dynamic landscape and on approach to the lake it's exciting to guess what state it will be in. The water disappears into an underground drainage system, the details of which we currently know very little about. This new study will be in two parts; the first uses a camera to take time lapse images of the lake, hopefully capturing it filling and emptying; the second will use water level loggers at various location to measure the rate that the lake is filling and emptying."

The study is ongoing and the first images from the time lapse photography are beginning to come through, recording for the first time the emptying and filling of the lake. This exciting project perhaps won't shed any light on the ghosts of Loughareema, but it will be able to solve the mystery of the disappearing water, and lead to a better understanding of the entire drainage system. 

To find out more about the Loughareema project, contact Dr Paul Wilson at paul.wilson@detini.gov.uk

Monday, 13 October 2014

Health check reveals how glacier is declining due to warming climate... by Lauren Noakes

Andrew on Falljökull
British Geological Survey©NERC
Researchers from the British Geological Survey have taken the very first comprehensive health check of a rapidly melting glacier. Their latest study reveals that their icy patient, the Falljökull glacier in south east Iceland, has been dramatically declining as it tries to adjust to recent changes in the climate.

The new findings on Falljökull show unhealthy changes in the glaciers behaviour and structure. Normal glacial patterns (growing in the winter and retreating in the summer) have been replaced by all year-round melting and rapid retreat of the margin of this Icelandic glacier, whilst its upper reaches continue to move forward. In fact the retreat has increased so dramatically over the last five years that there has been complete detachment of the stagnant lower section, like a lizard losing its tail.
The team have published further information regarding this 'downsizing' behaviour on the BGS website.

“Over the past two decades due to the increasingly warmer summers and milder winters Iceland’s glaciers have been retreating at a dramatically accelerated rate.” commented Jez Everest, a glacial geologist at the BGS and co-author of the new paper.
Andrew on Falljökull. British Geological Survey©NERC
The research could help scientists understand how other glaciers around the world, exhibiting similar early warning signs, could behave in the future. Working out how glaciers respond to changing climate is vitally important in a world where millions of people rely on them for drinking water and hydroelectric power.

Emrys Philips on Falljökull
British Geological Survey©NERC

Emrys Phillips, BGS research scientist and lead-author of the paper said, “We took a fully 3D view deep inside Falljökull and what we saw was rapid changes in the structure, a form of ‘downsizing’, to adjust to the changes in climate. We think that other steep, mountain glaciers around the world may be responding in a similar way, rapidly adjusting their active length in response to recent warming of the climate.” He also added “This type of behaviour has never been described before.”

Previously retreating glaciers are thought to behave in one of two ways: ‘active retreat’ where its margin oscillates backwards and forwards each year, retreating during the summer due to melting and moving forward in the cold winter months; and ‘passive retreat’ were it no longer moves but simply melts away like a giant ice cube (stagnates). Strangely, Falljökull does not fit neatly into either of these ‘pigeon holes’.

Using cutting-edge technologies BGS scientists were able to look inside the glacier. The monitoring techniques used by the team include:
•    Ground Penetrating Radar to image inside the glacier and map the ice’s internal structure
•    Terrestrial Laser scanning (LiDAR) to create a detailed 3D model of the surface of the glacier and surrounding glacial landforms
•    four Global Navigation Satellite System (GNSS) stations installed onto the surface of the glacier to record its velocity
•    digital mapping and measuring of the glaciers surface structures (fractures, crevasses, faults)

 Using these techniques, the new study shows that between 1990 and 2004 the margin of Falljökull was ‘active’ with its seasonal oscillations leaving behind a series of ridge-like mounds of sediment which were pushed-up by the glacier during the winter months. But in 2004-2006 the margin of the glacier stopped moving altogether and began to melt back at an increasing rate.

Jez and Andrew on Falljökull
British Geological Survey©NERC
However, time lapse photography and the GNSS/ GPS stations on the glacier surface clearly show that ice is still descending the icefall, and that the upper part of Falljökull is still flowing forward at between 50 and 70 meters per year.

The researchers have traced a large thrust fault cutting straight across the glacier just below a marked bulge in the glacier surface. This thrust is allowing the still ‘active’ upper part of the glacier to be pushed (thrust) over the lower reaches which stopped moving in 2004-2006.

The new study has been accepted for publication in the Journal of Geophysical Research: Earth Surface, a publication of the American Geophysical Union. The paper is being published later today but the accepted copy can be found online and open access here: http://onlinelibrary.wiley.com/enhanced/doi/10.1002/2014JF003165/#readcube-epdf 

A good place for further reading is the BGS website. 


In front of Falljökull. British Geological Survey©NERC

Notes to the media:
Jez and Emrys are available via email for futher questions. Please contact me on:

Office        +44 (0)131 667 1000      Mobile        +44 (0)7772 043 180
Email:        lnoakes@bgs.ac.uk        Twitter        @laurennotes

Friday, 10 October 2014

Searching for Tsunamis in the Aleutians... by Chris Vane

Chris Vane takes us to the unhinhabited island of Sanak, Alaska in search of the unique sandy fingerprints of old tsunamis. The team's mission is to improve our knowledge of past events so we better understand the hazard of future tsunamis... 

Over the past decade coastal communities around the world have been subject to a number of tsunamis that occur at seismically active subduction zones such as those in Sumatra-Andaman (2004) and Tohoku-Oki, Japan (2011). Globally we are unprepared for such catastrophic events such as the Boxing Day tsunami and know relatively little about their frequency. Although historical records of tsunamis do exist these are patchy and only in a few places such as Cascadia and perhaps Japan do they extend back far enough in time to allow some insight into the hazard from tsunami impact. 

From left to right: Location of Sanak in the Aleutians. Beautiful scenery of Sanak. Me with a GPS station on Sanak.
Reconstruction of large earthquakes and their associated tsunami requires the detailed inspection, collection and analysis of coastal sediments that, as well as dating and sedimentary evidence, may contain the unambiguous chemical and or biological fossil signature of a tsunami. Earlier international collaborations in Oregon and Japan suggested that a suite of organic geochemical compounds such as alkanes, hydrocarbons and glycerol dialkyl glycerol tetraethers (GDGT) from Archea and Bacteria could, when used together, help distinguish a tsunami origin from other extreme events such as storm over-wash and or fluvial flood. This cutting edge research led to Alaska to head up the geochemical portion of a grant aimed at tracking past tsunamis in the Aleutian Islands on the boundary between the Pacific and Bearing Sea. This area is of interest to geoscientists because it frequently generates earthquakes and tsunamis due to multiple cycles of strain accumulation and release on the megathrust faults of the Pacific plate subduction zones.

Example of a GDGT marker compound for
marine and soil organic matter

In early August I joined a multi-disciplinary team of six US scientists from USGS and one from University of Rhode Island to track ancient tsunamis in sediments. We lived and worked on the uninhabited Island of Sanak which is situated mid-way along eastern Alaska- Aleutian arc that extends 1600 km from southeast Alaska westward to Kamchatka. In reality it’s four flights and an eight hour trawler boat ride from Cold Bay, AK. The first few days in the field were spent gouge coring and ‘calibrating’ everyone’s sediment descriptions so that the team could break into tsunami hunting ‘pairs’ so that the island could be fully surveyed using a consistent terminology. We hiked around 20 km each day for the next 10 days gathering up geochemical, lithologic and stratigraphic samples from south facing valleys. We revealed multiple tsunami sand layers sandwiched between tephra (possibly from the ever looming Shishaldin, Isanotski and Pavlof Volcanoes) by coring through peats using a ‘Russian auger’ or digging trail pits. Additional evidence of a recent historical tsunamis was provided by fugitive logs stranded high above cliffs (the island has no trees). 

From left to right: The trawler from Cold Bay. Tsunami sand layer. Wild horses of Sanak.

I left the island with not only 50 kg of sediments samples but amazing memories of the landscape, incredible wildlife which included thousands of spawning salmon, nesting eagles, wild horses and the occasional sea otter. The samples now at BGS Keyworth are excellent examples of multiple tsunami sands and myself and the organic geochemistry team have already begun preparing them for molecular level analyses which will tell us about the contribution of marine as compared to terrestrial organic matter inputs to the sediments.


Below are some papers I used to inform my blog and which you may find interesting further reading:

KHAN, N. S., HORTON, B. P., MCKEE, K. L., JEROLMACK, D., FALACINI, F., ENACHE, M. D. & VANE, C. H. 2013. Tracking sedimentation from the historic A.D. 2011 Mississippi River flood in the deltaic wetlands of Louisinana, USA. Geology, 41, 391-394.
NIKITINA, D. L., KEMP, A. C., HORTON, B. P., VANE, C. H., VAN DE PLASSCHE, O. & ENGELHART, S. E. 2014. Storm erosion during the past 2000 years along the north shore of Delaware Bay, USA. Geomorphology, 208, 160-172.
PILARCZYK, J. E., HORTON, B. P., WITTER, R. C., VANE, C. H., CHAGUÉ-GOFF, C. & GOFF, J. 2012. Sedimentary and foraminiferal evidence of the 2011 Tōhoku-oki tsunami on the Sendai coastal plain, Japan. Sedimentary Geology, 282, 78-89.

* Editor - i've boldly paraphrased from the mightly father of modern geology, Mr James Hutton, who actually said "from what has actually been, we have data for concluding with regard to that which is to happen thereafter."

Aurora Borealis goes (Geo) Social... by Emma Bee

Emma Bee explains why our latest citizen-science tool will have the Twitterverse looking to the skies...

Aurora over Deeside, Scotland. Photo courtesy
of Jim Henderson Photograph
Over half of the population of the UK own a smartphone, and about the same number of people uses social media such as Twitter. For us this means millions of potential reporters of real-time events and in-the-field data capturers, creating a new source of scientific information that could help to better understand and predict natural processes.

Obtaining information about a hazard event as it unfolds, such as a flood or earthquake, was, until relatively recently, largely limited to the professional media. However, as is seen more and more often social media is being used extensively to gain live situational awareness. During the Japanese Earthquake in 2010 videos were posted on YouTube hours before the same clips were used by the professional media. More and more people are looking to social media as an additional, more immediate source of information.

GeoSocial is a tool currently being developed by BGS for retrieving and displaying information relating to geoscience (initially geohazards) that people have posted on social media sites. Although still in its infancy, the aim of GeoSocial is to explore whether BGS can make use of the wealth of information, publically available through these sites, to help advance scientific understanding and provide better, or, more - timely, advice.

It employs both passive (i.e. obtaining information which people have shared and which can be retrieved without requiring them to do anything beyond their normal behaviour and actions) and active crowdsourcing techniques.

In this first release, GeoSocial has been developed to retrieve information about aurora sightings in the UK posted on Twitter. When a geomagnetic storm forecast is issued, a common question posed to scientists is "How far south will the aurora borealis be seen?" Current projections do not always match sighting reports received after an aurora display, but by using social media, it is hoped that this new source of data will help improve our scientific projections of these events.

So next time there's a Space Weather alert and you've been lucky enough to see the Aurora get Tweeting. Your Tweets will populate a map (above) where we'll all be able to see how far south the aurora is being sighted in real-time!

Tweet the hashtag #BGSaurora, the event's location (postcode: loc[EH9 3LA], town name: loc[Edinburgh], or geotag your tweet using the tweet location feature), and comments or pictures.

You can follow the BGS Geomagnetism Team on twitter using:

GeoSocial Project Leader

Tuesday, 7 October 2014

Imaging inside a glacier; clues to a changing climate? By Carol Cotterill

The morning was cold and the 80 mph wind brisk as three BGS scientists trudged across a barren landscape, battling steep debris covered slopes, armed with more than 50kgs of equipment including a Ground Penetrating Radar (GPR), a remote controlled helicopter and a packet of hobnobs. Some who know the legend of the Little People who live in the rock formations in Iceland might suspect this was an emergency drop of biscuit rations to a remote clan of Icelandic Elves dwelling deep beneath a glacier. However, Dr Emrys Phillips soon gave me a more scientific explanation!

Glaciers respond to a changing climate in a variety of ways. The aim of this study of the Kviarjökull glacier in southeastern Iceland was to map the 3D structural architecture of the glacier, including mapping fractures, faults and crevasses, to try and understand how the glacier moves and responds to changing inputs, such as temperature.” 
Andy Finlayson working with the GPR.
Image courtesy of Emrys Phillips

Working with two colleagues from Durham University, the team found that only a portion of the glacier had moved since the last visit in 2013, but the move was significant, with the forward pulse creating a mound of sediment in front of it called a push moraine. How and why this pulse has happened will be one of the questions they hope to address in the coming months as they review the aerial imagery taken by the helicopter, and the 7km of GPR results that image inside the ice itself.

And the role of the Hobnobs? Food for thought..........


Panoramic view of Kviarjökull. Image courtesy of Emrys Phillips

Carol Cotterill

An unscrupulous woolly investigation: a look at the more unusual work at BGS... by C Pennington

Jim Riding and his microscope
Dr Jim Riding is a world-renowned palynologist, which means he studies pollen to reconstruct past environments and provides assessments of geological age.  He has worked on a very wide range of projects over the years, some more unusual than others... 
It was a typically busy day in the office for Jim when, out of the blue, the phone rang.  What was to follow was an investigation into the murky world of fraud.

The caller worked in the wool industry and explained that he knew of an unscrupulous trader whom, he suspected, was making false claims about his wool.  The wool in question was marketed as the finest British produce expected to sell at a premium price, but it didn’t look like kind of wool it claimed to be.  The caller had studied geography at university and, remembering pollen analysis, phoned Jim in the hope that he might be able to determine where the wool had come from.

Used to dealing with geological materials, no one in the BGS palynology laboratory had ever prepared wool for this kind of analysis before.  The first job was to work out how to get the pollen out of the wool.  This proved quite tricky as Jim explained:
We had to use a warm solution of potassium hydroxide that, if too strong a concentration, would actually dissolve the wool!
From the analysis, Jim found pollen from the Southern Beech tree (Nothofagus) – a plant mostly confined to Australasia or South America – and therefore successfully proved the wool could not be British!

If you would like to read more about the work Jim does, he has published a substantial volume of papers and other publications that are available via NORA.

Catherine Pennington

Tuesday, 23 September 2014

Hidden Hunger in Malawi...by Edward Joy

Edward in his panama hat out in Malawi
A few months back we shared a great post about the award winning PhD student (working at BGS and University of Nottingham) Edward Joy, whose project tackles the important issue of hidden hunger in Malawi. Now Edward tells us in his own words about his research and years of research in the field...

The last couple of years have been a steep learning curve for me: a faulty radiator can write off your engine; laptop battery life is everything; and you may need to hire guards to keep monkeys off your maize trials! These have been valuable lessons as I plan to continue similar research in Ethiopia starting in December. Overall, it has been a pleasure living in Malawi, a country endowed with some very beautiful landscapes and incredibly friendly folk – it’s not uncommon on sampling trips to be invited into farmers’ houses for roast pumpkin and peanuts.

My project aim, using cross disciplinary science, is to improve the accuracy and spatial resolution of dietary mineral supply estimates in Malawi and to investigate the potential of agricultural solutions to mitigate dietary mineral deficiencies.  The Malawi Ministries of Agriculture and Health have been very supportive and hopefully the outputs will be useful to them, for example in developing fertiliser policies and targeting nutrition strategies.

So here's a look in more detail at the work I've been doing out in Malawi...

Hidden hunger

Humans require 22 mineral elements for their wellbeing including calcium (Ca), iron (Fe), magnesium (Mg), selenium (Se) and zinc (Zn). The biological functions of elements include bone structure (Ca and Mg) and, as constituents of proteins, immune response (Se and Zn) and oxygen transport (Fe and Zn). Adequate quantities of these elements in diets is thus necessary for food security; inadequate intakes, or poor absorption in the gut due to e.g. diarrhoea, can lead to ‘hidden hunger’. It’s termed ‘hidden’ because the physical effects are not obvious, unlike the symptoms of protein or energy undernourishment, and because it is often hard to quantify the prevalence of such malnourishment in populations.

Dried fish at a market in the capital city, Lilongwe
Malawi hasn’t witnessed widespread famine since 2005, although certain regions are prone to food shortages due to both drought and flooding. But it may be that hidden hunger is widespread and that deficiencies of certain minerals and vitamins are a major health burden. There is evidence to suggest this is the case, for example with Se deficiency (Gibson 2011; Eick 2009; Hurst 2013) and Zn deficiency (Gibson1998; Siyame 2013); but there is no data at the national level.

Element concentrations

Malawi is predominantly a subsistence economy in which households grow their own food. The dietary supply of elements is thus dependent on which crops households choose to grow and what those crops contain. Element concentrations in crops depend on the availability of elements in the soil: for example, in low-pH soils Se is predominantly found in forms unavailable for plant uptake, whereas in soils with pH >6.5 Se is generally soluble, mobile and readily available for plant uptake.  There are limited data on crop composition in Malawi so we worked to fill this gap, collecting over 600 crop samples representing 97 food items for multi-element analysis by ICP-MS (Joy et al. 2014). We found that soil type affects crop composition, with maize and leafy vegetables from calcareous soils having greater Ca, Cu, Fe, Mg and Se concentrations than those grown on non-calcareous soils. Maize also had greater Zn in samples from calcareous soils, whereas leafy vegetables had greater Zn from non-calcareous soils.

The household survey

Edward presenting the team’s work at Mzuzu University
in northern Malawi
To find out what crops households are growing and what foods they are eating, the Malawi Household Survey (World Bank and Malawi Government) has proved a valuable resource. In this survey, >12,500 households were asked what foods they consumed over the last seven days. We are working to match this data to our composition data to generate dietary mineral supply estimates by region and soil type. One of our early findings is the critical importance of small fish in meeting Ca, Se and Zn requirements. Most fish production is from Lake Malawi, a Rift Valley lake that runs much of the length of the country. It’s sometimes known as the Calendar Lake as it’s roughly 365 mile long and 52 miles wide. Fish are sundried before traders take them inland. Although fish is a vital source of minerals in the diet, households require some cash to purchase them. It will be very interesting to see the relationship between household income and consumption of fish.
 The FAO and World Bank have just published a book called ‘Analyzing Food Security Using Household Survey Data and at the recent Micronutrient Forum held in Addis Ababa, Ethiopia, I found that other research groups including IFPRI are doing similar work to us. It’s great to see the hard work now contributing to scientific knowledge as we write up, publish and present our findings.

Thanks for reading

Here are my references:

Eick F, Maleta K, Govasmark E, Duttaroy AK, Bjune AG (2009) Food intake of selenium and sulphur amino acids in tuberculosis patients and healthy adults in Malawi. Int J Tuberc Lung Dis 13: 1313–1315

Gibson RS, Bailey KB, Ampong Romano AB, Thomson CD (2011) Plasma selenium concentrations in pregnant women in two countries with contrasting soil selenium levels. J Trace Elem Med Bio 25:230–235

Gibson RS, Huddle JM (1998) Suboptimal zinc status in pregnant Malawian women: its association with low intakes of poorly available zinc, frequent reproductive cycling, and malaria. Am J Clin Nutr 67:702–709

Hurst R, Siyame EWP, Young SD, Chilimba ADC, Joy EJM, Black CR, Ander EL, Watts MJ, Chilima B, Gondwe J, Kang’ombe D, Stein AJ, Fairweather-Tait SJ, Gibson RS, Kalimbira AA, Broadley MR (2013) Soil-type influences human selenium status and underlies widespread selenium deficiency risks in Malawi. Sci Rep 3: 1425. DOI: 10.1038/srep01425
Joy, EJM, Broadley, MR, Young, SD, Black CR, Chilimba, ADC, Ander, EL, Barlow, TS and Watts, MJ*. (2014). A spatially refined food composition table for Malawi, Science Total Environment, (accepted Sept. 2014)

Siyame EWP, Hurst R, Wawer AA, Young SD, Broadley MR, Chilimba ADC, Ander EL, Watts MJ, Chilima B, Gondwe J, Kang'ombe D, Kalimbira A, Fairweather-Tait SJ, Bailey KB, Gibson RS (2013) A high prevalence of zinc- but not iron-deficiency among women in rural Malawi: a cross-sectional study. Int J Vitam Nutr Res 83: 176–187

Friday, 19 September 2014

One of our ecological footprints… By Sarah Bennett

Landfills provide a way of hiding away the rubbish we create – out of sight out of mind.  However, research now shows that chemicals leaching from these landfills are polluting our rivers.  The work led by BGS scientist, Daren Gooddy, found that approximately 27.5 tonnes of ammonium a year finds its way from unlined landfills on the outskirts of Oxford, through a flood plain and into the River Thames. Here Sarah Bennett, a Stable Isotope Research Geochemist at BGS and co-author of the research, explains more...
Once ammonium enters the rivers, it breaks down to nitrogen.  The extra nitrogen can trigger excessive plant growth and decay, damaging water quality and starving fish and other aquatic organisms of the oxygen they need to survive.  Scientists are most worried about so-called blue-green algal blooms, which can produce toxins capable of killing wild animals, livestock and domestic pets.  In people, they can cause skin rashes, nausea, stomach pains, headache and fever.
Sampling groundwater on a floodplain in the winter is not always
      straight forward and requires both innovation and improvisation    
The source of the ammonium was identified with isotopes, a chemical fingerprinting technique, and this enabled the team to attribute the ammonium to household waste.  This isn’t the first time isotopes have been used to identify human impacts on the planet.  Back in August, Jonathan Dean discussed how isotopes provide evidence of human activities 2000 years ago during mining and smelting and more recently during the industrial revolution.  His work suggests that we are in a new geological age, the Anthropocene: where humans impact and change the environment (read Jonathan's blog here).

Aerial view of Port Meadow, Oxford, during flooding
As a society we are concerned with our current and future activities on this planet, but we also need to deal with the ramifications of our past mistakes.  These landfills are one such example; we’ve learnt to line our landfills with thick clay to prevent chemical leaching, but we still need to deal with the unlined landfills that represent thousands of historic landfills across the UK.  We’ll be drawing up new management plans for floodplains on the margins of towns and cities as a result of this work. 

You can read more about this research in the journal Science of the Total Environment.