Wednesday, 19 February 2014

Ancient Climate Secrets by Jonathan Dean

Standing on the rock on which
the first peace treaty in human
history was signed between the
Hittites and the Egyptians
Jonathan Dean started working as a Stable Isotope Apprentice in NIGL this January after he finished his PhD research at the University of Nottingham. Here he tells us a little bit about his research into how lake sediments are revealing secrets of past climates...

I carried out my PhD research (between 2010 and 2013) on the chemistry of lake sediments from central Turkey, supervised by Dr Matthew Jones and Prof Sarah Metcalfe at the University of Nottingham and Prof Melanie Leng and Dr Steve Noble in BGS.  The research was aimed at reconstructing changes in the hydroclimate (i.e. wet vs. dry) of the region over the past 15,000 years. Previously, there were no reconstructions of hydroclimate from the region spanning this time period that were analysed at a sufficiently high resolution to allow changes in climate from one decade to another to be examined. There were a couple of key motivations for my work. Firstly, Turkey is an important region in human history, as it was here that some of the first farming communities sprang from ~10,000 years ago and where important civilisations such as the Hittites developed. My climate data will allow archaeologists to better investigate the links between societal development and climate change.

The other motivation for my research was so we had a climate record which could be better compared to those from other parts of the world, so we can consider the drivers of Near East hydroclimate. In particular, I wanted to investigate how abrupt climate changes seen in the North Atlantic, such as one that occurred 8,200 years ago (the infamous 8.2 event), are expressed in this region. Understanding the form and drivers of these sorts of climate perturbations is particularly important given the concern that human forcing of climate may increase the probability of such events occurring in the future.

Nar lake in July 2010
In 2010, a group from Britain, France and Turkey travelled to Nar lake in Cappadocia, central Turkey and retrieved a 21.5 m long core of sediment from the lake. The top-most sediments were deposited in 2010 and the bottom-most ~15,000 year ago. I then took samples from the sediment at intervals of 30 years or less, and analysed the changes in the ratio of one type (or isotope) of oxygen to another in the calcium carbonate in the sediment. This allowed me to reconstruct how the hydroclimate of the region changed through time. I found some large shifts than occurred within just a few decades. The climate seems to have been wet at the time agriculture developed and droughts appear to have occurred at the same time civilisations such as the Hittites collapsed. Some of this work has been published and I will be writing up further papers in the coming months, as well as being examined for my doctorate next month!

Undertaking isotope analysis on hundreds of samples for my PhD has put me in good stead for my job as a Stable Isotope Apprentice at NIGL. I’ve spent the first few weeks preparing samples and analysing them for oxygen and carbon isotopes, as well as getting on with writing papers from my research.

Hot air ballooning over the badlands of Cappadocia

Jonathan @jrdean_uk

Monday, 10 February 2014

Colours, Shapes & Science of Iceland (2/2) by Lauren Noakes

Yesterday I blogged about the art exhibition which our Iceland team have been a great part of. I'd tantilised you with the prospect of finding out how their science could impact people round the globe and left you with the question - where does all the water from the glacier go? 

So to quench your palpable intrigue here's Part 2/2 where we hear from the groundwater experts on the Iceland project. Again this is written by me, Lauren, your intrepid press officer in BGS Edinburgh.

Also on display at the exhibition is
Andrew's famous fieldwork hat!
Hydrologist Dr Andrew Black from the University of Dundee explains why a lot of his time in Iceland is involved with trying to measure the volume of water in the river. "All the water from the glacier catchment emerges into the river system via a lake"

“It’s about trying to understand how the outputs of this large and hostile glacial system link to its inputs [about 7m of snow and rainfall a year]. If we succeed in that we can make better predictions about how long the ice has left before it either completely vanishes from this part of Iceland or if some new equilibrium might be achieved.” 

Jean worked alongside Andrew on the bridge over the river "stopping traffic so he could safely dangle bits of equipment into the river to measure its flow". Jean also said she was spooked by the river because “when I came back to it a few minutes later the water level had visibly risen, you were actually experiencing the glacier melting before your very eyes, it was a shock”. 

Whilst i sat in the audience listening to Andrew talk about his experiences it occurred to me that this band of scientists are in a very unique position. For many years now they’ve been privileged to witness, record and study in detail the changes to this environment that not many other people ever have or will. With their arsenal of science equipment including weather stations, boreholes, seismometers, webcams…….(the list goes on here)..... I don’t think even the locals know the glacier in the intimate and in-depth way this team do. More importantly this work isn't just about doing science for science's sake. What they've learned, through hard graft and ongoing collaborations, has the real potential to benefit hundreds of millions of people around the globe. Brighid O Dochartaigh, hydrogeologist at the BGS, explained more of this in her talk. 

Brighid proudly stands next to her Icelandic
jumper on display at the exhibition. Hand
knitted by herself with wool from the
island it's a thing of beauty coveted
by her collegues!
“We’ve discovered there’s a thick permeable aquifer made of sand and gravel that’s sat just in front of the glacier, in the area called the sandur. During winter there’s more water flowing underground through here than there is water flowing in the river. Close to the glacier this aquifer is filled in part by the river but further away it’s filled by mostly rainfall. This could be really significant and important for future water resources around the globe, not just in Iceland.”

“In many areas people rely extremely heavily on melt water from glaciers, in areas like the Himalayas  people rely on it for drinking water. So if these glaciers disappear, as we’re seeing on Iceland, then that's a massive problem and we’ll have to find replacement sources of water. The work we’re doing on Virkisjokull suggests there could potentially be a large store of water underground that’s replenished by rainfall and not glacial melt water which clearly could be really important for those living close to it. So I’m lucky enough to work in this amazing place and do work that could have important ramifications all around the world”. 

With potentially global benefits to the work the team are doing in Iceland it’s clear to me that grabbing every chance to communicate their work is essential. What could be more important, other than the work itself, than raising awareness of not only our local ancient environments and evolving landscapes but the future security of water around the globe? 

By doing outreach collaborations with CechrArtist in Residence Jean Duncan, and previously with the Royal Society Summer Science Exhibition (see our 2013 online outreach on that), the team are making their work accessible and understandable. Not only that but they hope such events will inspire a whole new generation of young and early-career scientists. Not only do you get great science by bringing different skills and people together but great art too.

Together again: scientists and artist reunite at Jeans 'Melt' exhibition
From left to right: Andrew, Verity, Jean, Brighid and Jez
Jean's closing comment: “I wanted to record the changes happening as the glacier is dying, nothing stays the same out there. The place, people, history, geology and geography came together and became a strong memory for me. What I came away with was a picture of this landscape that’s never going to be the same again because it’s changing constantly. So I’ve made these sketches but when everyone goes back in April it’s not going to look the same. It was a really unique opportunity.”

Thanks again for reading,

Please feel free to leave comments below. I'll endeavor to get your science questions answered by Jez and the team, but please be patient with me.
Go see Jean’s ‘Melt’ exhibition NOW. It’s on in the Tower Foyer Gallery, University of Dundee and runs until 29th March. For opening times of the Tower Building see the previous link. 

Sunday, 9 February 2014

Colours, Shapes & Science of Iceland (1/2) by Lauren Noakes

With scenes like this (nr the BGS Observatory in Iceland) is it any wonder that the disciplines of art and science came together here? (photo by Brighid)
In the spring of 2013 artist Jean Duncan, Cechr Artist in Residence, came to stay with the scientists during their fieldwork season. Yesterday saw the launch of her exhibition ‘Melt’ and I went along to find out more about the BGS Iceland Observatory, the work and how it inspired this beautiful art from Jean.…. 
Written by me, Lauren, your intrepid press officer in BGS Edinburgh 

“I didn’t expect there would be lime green in amongst the grey and white of the ice”

“on the ice there are these turquoise streams running down deep blue holes” 

Only ever having seen Iceland through the words, images and models of scientists I was fascinated to hear how Jean described the daunting expansiveness of the landscape cut with vivid colours like lime green and turquoise.

“it was really wonderful to have Jean along because it was like seeing the landscape and process on the environment through a new set of eyes and it really refreshed our passion for this beautiful and fragile place” Jez (photo by Brighid)

Jean, who accompanied the team on their September fieldwork, was surprised not only by the landscape’s colours but by the shapes! It turns out the triangles Jean sketched, which littered the landscape, weren't random but a pattern explained by science. Jean explained “it’s called the angle of repose, something that happens when soil or sediment collapses and it always ends up at this same angle, so whilst it’s clearly a very chaotic landscape there is this pattern running through it with these triangles” Turns out the sediment makes a uniform 36degree angle of repose. Who knew!

After Jean introduced her work it was the turn of the scientists to step up and do their thing. Jez Everest, BGS Iceland Observatory Team Leader, was first up to introduce the Virkisjokull glacier. “She’s a lovely wee glacier but she’s in trouble. She’s been melting very rapidly over the last 5-6 years and that is on the back of a continued melting period since in the 1990’s and previously since the 1930s.  So she’s a glacier in decline, as are all glaciers on Iceland and most around the world. That’s why we work here, and because she responds quickly to changes in regional climate so we can pick out the drivers and responses to environmental change."

“In just two years the glacier has retreated 70m from it's snout and thinned from the top by about 20m” Stark statistics - of which you can find more of, and accompanying research and information, on the Observatory's webpage.

“I work onto wet plaster, paint on it then scratch into it and sometimes run it under the tap. Working away at it, it’s a wee bit like what’s happening in the environment, it’s all rubbed and moved and changing all the time” Jean (photo by Brighid)
“These environmental changes happening on the glacier allow us to see how our own landscapes may have evolved. Scotland and Ireland were once very similar environments to that in Iceland. In 2009 in Iceland we witnessed the formation of these sinuous eskers, geological features that we can see preserved in Scottish landscapes today. Eventually Virkisjokull and the surrounding landscape will be free of ice and will just be one big lake, there’ll be no evidence that there was ever a glacier here.”

It’s shocking to think this could happen in our children’s lifetime, maybe even our own. It’s predicted that in only a few hundred years all the ice on Iceland will have gone.

So where does all the water from the glacier go? For that you'll need to ask a water expert! Luckily there are a few on the project and talking next at the event......

Brighid O Dochartaigh (BGS hydrogeologist) studies the subsurface water in the area just infront of the glacier called the sandur, and Andrew Black (University of Dundee Hydrologist) monitors the surface water coming out of the glaciers catchment area. Tune in tomorrow to hear about how their work on Iceland has the potential to positively impact people all around the world. 

Until then, thanks for reading

At the launch of Melt exhibition, some of the scientists who took Jean out on the ice
From left to right: Verity Flett, Andrew Black, Brighid Ó Dochartaigh, Jez Everest

Go see Jean’s ‘Melt’ exhibition NOW. It’s on in the Tower Foyer Gallery at the University of Dundee and runs until 29th March. For opening times of the Tower Building see here.  

Please feel free to leave comments below. I'll endeavor to get your science questions answered by Jez and the team, but please be patient. Thanks again.

Friday, 7 February 2014

Have Volcanic Super-Eruptions Impacted on the Course of Human History?By Prof Melanie Leng

The ancient Toba caldera (a basin left by
the volcano after eruption) from space is
now occupied by a huge lake (@NASA)
Today Melanie Leng, an isotope geochemist and palaeoclimatologist at the BGS, tells us about the Toba super volcano in Sumatra, Indonesia, which has erupted on many occasions over geological time. 

One very destructive eruption of Toba occurred around 74,000 years ago, an event that has been estimated to have ejected thousands of cubic kilometres of volcanic ash and rocks into the atmosphere which spread far and wide both North and West of Sumatra on prevailing winds. Evidence for the volcanic ash is seen today on the Indian subcontinent and in the Arabian and South China Seas. The ejection of so much ash and volcanic gases into the atmosphere is thought to have reflected the suns heat and there is evidence that global cooling occurred or a ‘volcanic winter’ for example in geochemical data from the Greenland ice cores. In other parts of the world the Toba eruption appears to have little impact, life went on undisturbed, in the African Great Lakes for example. One of the big unanswered questions about Toba is whether the eruption impacted on human populations. There are theories suggesting human population decreases (a genetic bottleneck) and a significant arid event could have altered human migration patterns for example.

Volcanic ash called tephra is made up of fragments
of glassy material that are ejected during volcanic
eruptions and can be used to identify volcanic
To assess the global influence of the eruption we need to look for evidence for environmental change at the time of the eruption around the globe*. From the southern Mediterranean (Balkans) we investigated lake sediments deposited 74,000 years ago for this evidence. Detailed geological detective work on the sediments using high magnification microscopes have so far not detected any evidence for volcanic ash from Toba. However we have found other clues from within the lake sediments that show a response to several years/decades of cold (volcanic winter) conditions. Shell fragments transported to the central part of the lake indicate lake level drop (cold dry conditions) and the geochemistry of the sediments suggest that the lake became more evaporated (less rainfall); while pollen preserved in the sediments shows trees died back as the SE Mediterranean experienced dark, cold summers and long cold winters.

In the context of human migration it is important to understand the climate of the southern Mediterranean (a conduit for humans leaving Africa) at this important period in history. Did the Toba eruption completely change the course of human history? Well the geology of the lake sediments definitely suggest harsher winters, so maybe this was a good reason to slow human migration? Isn't geology amazing? 

Prof Melanie Leng (@MelJLeng) is an isotope geochemist and palaeoclimatologist at the BGS. 

This research is in collaboration with scientists in Germany and Italy.
*Wagner, B., Leng, M.J., Wilke, T., Bohm, A., Panagiotopoulos, K., Vogel, H., Lacey, J.H., Zanchetta, G, Sulpizio, R. 2014. Distinct lake level stand in Lake Prespa (SE Europe) at the time of the 74 (75) ka Toba eruption. Climate of the Past, 10, 261-267.