Thursday, 28 May 2015

Carnegie Trust success for coral reef team

Dr Heidi Burdett, a MASTS Research Fellow in the Department of Earth and Environmental Sciences (DEES) has been successful in securing a Collaborative Research Grant from the Carnegie Trust for the Universities of Scotland, together with Drs Nick Kamenos (University of Glasgow) and Sebastian Hennige (Heriot-Watt University).
Millions of people around the world depend on coral reefs for their livelihood. However, in recent years the 'health' of corals, and their associated ecosystems, has deteriorated in many areas putting communities at risk. This Carnegie-funded project will investigate the response of tropical corals to environmental change, helping us to better understand the observed deterioration in coral reef ecosystems.

Related article: Effects of reduced salinity on the photosynthetic characteristics and intracellular DMSP concentrations of the red coralline alga, Lithothamnion glaciale. Marine Biology 162:1077–1085: DOI 10.1007/s00227-015-2650-8

Thursday, 26 February 2015

The first common market

Long before we had mountains of grain and vast lakes of wine accumulating to excess across the continent our ancestors had worked out that the best entrepreneurial way to stay ahead was through trade with as wide a market as possible. A study to be published in Science this week describes the first evidence for grain traded across Europe 8000 years ago, 2000 years before the accepted beginning of farming in Britain.

Divers at Bouldner Cliff with flints (The Maritime Trust)
The team of scientists, which includes Dr Richard Bates from the Department of Earth and Environmental Sciences at the University of St Andrews, Prof. Vincent Gaffney from the University of Bradford and the Universities of Warwick, Birmingham and Southampton studied two submerged sites at the extreme ends of Britain, off the shores of the Isle of Wight and Orkney, to discover sediment sequences that contained wheat grains. In the southern site, einkorn DNA (an early form of farmed wheat) was collected from material that had previously formed a land surface which was later sealed by sediment and submerged by rising sea levels. When the grain was dropped, the Mesolithic people were leading a hunter-gatherer existence as farming had only spread as far as Southern Europe. As the einkorn was not native to Britain, in order for it to have reached this site, there must have been contact between the people of Briton and the Neolithic farmers. This contact could even have been across narrow land bridges over what is now the English Channel and southern North Sea.

Flints from Bouldner Cliff
(The Maritime Trust)
The novel ancient sediment DNA analysis used in the study could unlock many other secrets of long lost areas, especially those surrounding our coasts. These areas were once at the heart of different societies but the locations make their study particularly challenging. For St Andrews, the work continues in the Orkney Isles around the iconic Neolithic landscapes where the team will use these techniques to continue investigating the land of the ancestors who constructed the monuments at these sites. [press release]

Science article: Sedimentary DNA from a submerged site reveals wheat in the British Isles 8,000 years ago (DOI: 10.1126/science.1261278).
BB News:  Scientists find evidence of wheat in UK 8,000 years ago

Tuesday, 17 February 2015

The Southern CO2 that helped end the ice age

Scientists have long puzzled over the processes that caused CO2 to rise and help end the last ice age. Leading theories have involved increased CO2 release from the deep ocean around Antarctica, but there has been no direct evidence to prove this happened.

Our study used the geochemistry of tiny planktonic fossil shells to reconstruct the amount of CO2 in waters around Antarctica during the end of the last ice age.  We were able to show, for the first time, that CO2 was indeed released from the Southern Ocean to the atmosphere, helping warm the planet and melt back the ice sheets that would have covered Scotland and much of the rest of Northern Europe and America.

Dr James Rae, of the Department of Earth and Environmental Sciences, who co-authored the study, said “intervals of CO2 and climate change in the past offer a fantastic opportunity for us to better understand the path of future climate.  As the ocean currently takes up about a third of the CO2 emitted by humans, it’s important to understand the controls on CO2 exchange between the ocean and the atmosphere so we can predict how ocean CO2 uptake may change in the future.  It’s also striking to think that CO2 change has contributed to climate changes in the past as dramatic as melting back a mile of ice on top of Scotland, and you’ve got to wonder what adding the same amount of CO2 to the atmosphere, but 100 times faster, will do to climate in the years to come.” [Nature 518, 219–222 (12 February 2015) DOI:
10.1038/nature14155, "Boron isotope evidence for oceanic carbon dioxide leakage during the last deglaciation"] [press release]

Friday, 19 December 2014

New research uses bioluminescent jellyfish as optical engineers

Researchers at St Andrews have produced the world’s first solid-state protein lasers, capable of record performance and some capable of self-assembly, by harnessing the optical engineering skills of bioluminescent jellyfish.

The findings, reported in the international journal Nature Communications ("Bio-optimized energy transfer in densely packed fluorescent protein enables near-maximal luminescence and solid-state lasers", doi: 10.1038/ncomms6722), have the potential to transform biomedical diagnosis of conditions such as cancer and advance the design of new materials. The work was inspired by the discovery that nature may have optimized - with sub-nanometre precision - the size of the molecules driving the bioluminescence of jellyfish to allow them to shine as brightly as possible. Professor Malte Gather from the School of Physics and Astronomy, together with Dr Seok Hyun Yun at Harvard Medical School and Massachusetts General Hospital, calculated that the green fluorescent protein molecule, which allows certain jellyfish to emit bright green light, has just the right size to strike an optimal balance between not losing energy to unproductive quenching and being able to squeeze as many molecules as possible into the light-emitting cells of the animal.

Fluorescent proteins derived from bioluminescent jellyfish
allow fabrication of efficient solid-state microlasers.
Under the right conditions, the protein molecules self-assemble
into a ring-shaped laser structure. Shown above are two such
lasers in action, made from a green and a red fluorescent protein, respectively.

Bioinspired by nature’s design, the researchers were able to make tiny solid-state lasers from these fluorescent proteins. The green fluorescent protein, generally known as GFP, is found the pacific jellyfish Aequorea Victoria where it is involved as energy acceptor in the natural bioluminescence of the animal. Several years ago molecular biologists isolated the section of DNA that tells the cellular machinery of the jellyfish how to produce GFP. Using genetic engineering this DNA can be used to confer the bright green fluorescence to other species - to bacteria, fruit flies, even to mice - a method that is widely used today to visualize cells or structures within cells under the microscope. Such measurements require only relatively modest protein concentrations. In the light-emitting organ of the jellyfish, however, the protein concentration is believed to be more than thousand times higher.

The scientists developed a number of different laser configurations. A particularly efficient design began to emit laser light when the power provided to it was less than what can be achieved in lasers based on state-of-the-art synthetic dyes. Another design makes use of the concept of self-assembly and allows the structure of the laser to form by itself. Professor Gather believes that beyond using GFP and other fluorescent proteins, the study of their structure and their optical properties can bio-inspire improvements of artificial emitters. [Press release]

Tuesday, 9 December 2014

Tree-rings reconstruct the South Asian summer monsoon index over the last millennium

The South Asian summer monsoon (SASM) is a major atmospheric synoptic climate system affecting nearly a quarter of the human population. Dr Rob Wilson, Department of Earth and Environmental Sciences, with co-authors from China have published a 1000-year-long reconstruction of SASM in the Nature Group journal Scientific Reports. They utilised 15 tree-ring chronologies to reconstruct the SASM index over the last millennium. The record generated is significantly correlated (r=0.7, p<0.01) with the instrumental SASMI record on annual timescales; this correlation is higher than that obtained in any previous study. The reconstructed SASMI captures 18 of 26 (69%) recorded historical famine events in India over the last millennium; notably, 11 of 16 short events with durations of 1–3 years are accurately depicted in the reconstruction. Moreover, the reconstructed SASMI is positively correlated with variations in total solar irradiance (TSI) on multi-decadal timescales implying that variations in solar activity may influence the SASM. Epoch analysis additionallyindicates that volcanic events may also drive some of the SASM variability about 2 years after major eruptions.
Figure: Time series of the reconstructed South
Asian summer monsoon index (SASMI) and total
solar irradiance (TSI) over the last millennium.

Shi, F., Li, J., and Wilson, R. 2014. A tree-ring reconstruction of the South Asian summer monsoon index over the past millennium. Scientific Reports, 4 (6739). DOI: 10.1038/srep06739.

Monday, 1 December 2014

The Building Blocks of Life

Searching for the essence of life on Earth, understanding climate change and investigating the spread of diseases - these are a few examples of the fundamental research that academics at St Andrews will be tackling with new equipment won under a competitive £0.5M NERC grant! This cutting edge analytical set-up combines a multi-collector inductively coupled plasma mass spectrometer (MC-ICP-MS) with a gas chromatograph (GC), and will be the first of its kind in the EU (and only the third in the world!). The NERC capital equipment fund bid was led by Drs Andrea Burke, Harry Oduro, James Rae, and Heidi Burdett from the Department of Earth and Environmental Sciences, supported by an interdisciplinary team including Profs David Paterson Ian Johnston, and Derek Woollins from the Schools of Biology and Chemistry.
The state-of-the-art clean mass spectrometry lab where the new
equipment will be housed
One of the exciting major applications for this new equipment is the measurement of sulfur isotopes. The study of sulfur has both pure and applied uses, as it is a key element on scales ranging from nano to global, and in processes ranging from climate forcing by volcanic eruptions, to the processing of sulfur-rich crude oils. This new analytical set-up permits the measurement of sulfur isotopes on samples a thousand times smaller than previously possible, and will provide valuable new information on climate sensitivity, metabolic pathways, and Earth resources and their recovery.

 For further information on this, contact Dr Andrea Burke.

Monday, 24 November 2014

Sulfate on the early Earth – how low was low?

Findings recently published in Science (“Sulfate was a trace constituent of Archean seawater”, DOI: 10.1126/science.1258966) suggest that sulfate – a key biological nutrient – could have been incredibly scarce in the Earth’s ancient oceans.

Sulfur is a crucial component of biomass and an important source of energy for microbial metabolisms. It also plays a central role in regulating atmospheric chemistry and global climate over geologic timescales.

Research vessel on Lake Matano, Indonesia.
PHOTO by Sean Crowe, University of British Columbia.
Researchers led by Dr Sean Crowe, a lead author of the study in the Departments of Microbiology and Immunology, and Earth, Ocean and Atmospheric Sciences at the University of British Columbia, collected samples from Lake Matano, Indonesia—a sulfate-poor modern analogue for the Earth’s Archean oceans – to examine the isotope effects associated with sulfur metabolisms under early Earth conditions. The team used state-of-the-art mass spectrometric approaches developed at California Institute of Technology to demonstrate that microorganisms in this lake fractionate sulfur isotopes at concentrations orders of magnitude lower than previously recognized.

“These results suggest that sulfate levels in the Archean could have been thousands of times lower than today, which would have had important consequences for the cycling of sulfur in the oceans and atmosphere, and for the evolution of early microbial ecosystems”, says Dr Aubrey Zerkle, a Lecturer in the Department of Earth & Environmental Sciences and collaborator on the study. Two additional papers published in the same issue of Science used similar techniques to examine sulfur isotope signatures of in ancient sediments from ~2.5 billion years ago. These studies suggest dynamic spatial and temporal variations of seawater sulfate during that time, supporting a low-sulfate scenario. However, both indicate that microbial ecosystems based on sulfur cycling still thrived, despite the lack of sulfate.