Network in Drummond Back online

Mar 16, 2013 7:00 pm

Power has been restored to the Network rack in Drummond Street, following the power outage earlier today. Access to services in Drummond Street should now be restored.

Greenland Hydrology

Mar 4, 2013 1:00 am

Researchers in Edinburgh’s Cryosphere Research group were involved in two papers just published in high impact journals that report on the seasonal evolution of the Greenland Ice Sheet’s hydrological system. The morphology of the subglacial drainage system critically influences both the dynamics and geomorphic impact of the ice sheet but until now, the structure and evolution of this system during the melt season have remained poorly understood. Using two types of hydrological tracer, fluorescent rhodamine dye and sulphur hexafluoride (SF6), injected into the drainage system over three melt seasons, we observed subglacial drainage properties and evolution beneath the Greenland Ice Sheet, up to 57 km from the ice sheet margin. The results indicate an evolution from a slow, inefficient drainage system to a fast, efficient channelized drainage system over the course of the melt season. The rapid development of an efficient and extensive subglacial drainage system suggests that the ice sheet may be less sensitive dynamically to increasing surface melt in a warming climate than previously suggested.

The two papers, in the Journal of Geophysical Research and Nature Geoscience, were led by Tom Cowton, a PhD student based in Edinburgh GeoSciences, and by colleagues at Bristol University respectively with input from numerous Edinburgh researchers (in bold below).

• Cowton T., Nienow, P., Sole, A., Wadham, J., Lis, G., Bartholomew, I., Mair, D. and Chandler, D. 2013. Evolution of drainage system morphology at a land-terminating Greenlandic outlet glacier, Journal of Geophysical Research, 118, doi:10.1029/2012JF002540.
• Chandler, D., Wadham, J., Lis, G., Cowton T., Sole, A., Bartholomew, I., Telling, J., Nienow, P., Bagshaw, E., Mair, D., Vinen, S. and Hubbard, A. 2013. Evolution of the subglacial drainage system beneath the Greenland Ice Sheet revealed by tracers, Nature Geosciences, 6, doi:10.1038/NGEO1737.

Colour as Information:

Jan 15, 2013 1:00 am

See the movie and paper made by Toshie Mizunuma and John Grace: Click here for Video

New in Nature - Trees & Drought

Nov 29, 2012 1:00 am

Beneath the bark of world’s trees pulses a finely tuned vascular system that transports billions of litres of water to the skies every day. This plant hydraulic system depends on a unique but unstable mechanism that is continuously challenged by environmental stress. New research in the current issue of Nature, lead by the University of Western Sydney and Ulm University in Germany, has found most trees, even those in rainforests, operate very close to their hydraulic safety threshold leaving them highly vulnerable to droughts of increased severity.

Drought is one of the major forces shaping our forest ecosystems. Over the last century, drought has been responsible for many incidences of large-scale forest dieback around the world. To make effective predictions of how the forest landscape may change in future, we need to first understand how plants work. One of the main problems that plants face during drought is to keep their ‘plumbing’ working. In order to take up carbon dioxide for photosynthesis and to cool their leaves, plants must transpire very large amounts of water every day. This water is absorbed from the soil and transported through a network of thread-like pipes that connect the roots to the leaves.

But this hydraulic pipeline is vulnerable and can break down during drought because of the development of air embolism. As soil dries, the water in these pipes comes under a large tension that can cause breakage of the liquid threads inside the plumbing system. So called “cavitation” of the liquid continuum inside the plant vascular system causes an air blockage, similar to the embolisms that can block the human circulatory system. As drought stress increases, gas accumulates in the system until the plant desiccates and dies.

Vulnerability to embolism is known to be one of the main factors determining drought effects on trees. However, plants vary dramatically in their tolerance of drought induced embolism making predictions of how forests might be altered more difficult.

Dr Brendan Choat from the University of Western Sydney and Dr Steven Jansen, from Ulm University in Germany, assembled an international team of 24 plant scientists to help create a global data synthesis examining all existing measurements of plant embolism resistance in forest species.

The researchers found that, as expected, species growing in wet forests were less resistant to embolism than those growing in arid areas. However, when vulnerability to embolism was compared to the moisture conditions typical for each species it emerged that most trees currently operate very close to their hydraulic safety threshold leaving them highly vulnerable to drought.

While plants vary greatly in their embolism resistance, their vulnerability to drought is the same across all forest types. Seventy percent of 226 forest species from 81 sites in the worldwide study operate with narrow hydraulic safety margins against potentially deadly levels of drought stress. The team found safety margins are largely independent of mean annual precipitation, illustrating global convergence in the vulnerability of forests to drought, with all forest types equally vulnerable to hydraulic failure regardless of their current rainfall environment.

The findings provide insight into why drought-induced forest decline is occurring not only in arid regions but also in wet forests not normally considered at drought risk. Trees take a ‘risky’ hydraulic strategy in a trade-off that balances growth with protection against the risk of mortality.

For trees, and the planet, the consequences of longer droughts and higher temperatures are potentially dramatic. For example, rapid forest collapse via drought could convert the world’s tropical forests from a net carbon sink into a large carbon source during this century.

However, the results of the study do not necessarily point to forest Armageddon. A forest may respond to climate change in a number of ways. For instance, some species may be able to evolve quickly enough to keep pace with a changing climate in one location, while others may spread into new locations, tracking their preferred conditions. Survival is largely dependent on species having enough time to respond to changes in the environment. The new dataset will be useful to better predict the balance between a declining or a healthy forest. It will also provide a better understanding of which species are likely to persist and which are likely to suffer and potentially disappear.

Original publication:

Choat B., Jansen S., Brodribb T.J., Cochard H., Delzon S., Bhaskar R., Bucci S., Feild T.S., Gleason S.M., Jacobsen A.L., Lens F., Maherali H., Martinez-Vilalta J., Mayr S., Mencuccini M., Mitchell P.J., Nardini A., Pittermann J., Pratt R.B., Sperry J.S., Westoby M., Wright I.J., Zanne A. (2012) Global convergence in the vulnerability of forests to drought. Nature. doi: 10.1038/nature11688.

Ellsworth Blue-ice Blog

Nov 20, 2012 1:00 am

First instalment from the Ellsworth Blue Ice Blog. Prof. David Sugden and Dr. Andy Hein from GeoSciences, along with Prof. John Woodward and Dr Stuart Dunning (both Northumbria) are blogging on their current Antarctic expedition - investigating whether or not the West Antarctic Ice Sheet (WAIS) survived the last interglacial.

Read the Ellsworth Blue Ice Blog

Edinburgh Graduate carries torch

Jul 27, 2012 1:00 am

Edinburgh Geographical Information Science graduate Wai-Ming Lee was nominated on behalf of the disaster-management charity MapAction to carry the Olympic Torch to Buckingham Palace, where it will be viewed by Prince Harry, and the Duke and Duchess of Cambridge.

Wai-Ming studied GIS in Edinburgh 1995-96 and has subsequently built his career in GIS, working for companies such as Hunting Technical Services and ESRI(UK). He is an active MapAction volunteer who joined the charity in 2004 and has been deployed to assist in the aftermath of humanitarian emergencies such as the Indian Ocean tsunami (2004) and Pakistan floods of 2010.

Scotland's Geodiversity Charter

Jun 15, 2012 1:00 am

Scotland's Geodiversity Charter was launched by Stewart Stevenson MSP, the Minister for Environment and Climate Change, on 6th of June. This is an important document for all for all GeoScientists working in Scotland.

It is available for download from the website of the Scottish Geodiversity Forum.

Forum website link

GeoScience papers featured

May 30, 2012 1:00 am

The journal Environmental Research Letters has just published its highlights of 2011 which features several staff from the School.

See full details

Featured staff include Greg Cowie, Gabi Hegerl (twice), Mark Rounsevell and Marc Metzger.

RGS Award to Charles Withers

May 8, 2012 1:00 am

Congratulations to Professor Charles Withers who has been awarded the Founder's Medal for 2012 of the Royal Geographical Society. This is a Royal Medal, approved by the Queen, and awarded in recognition of his work in the encouragement and development of historical and cultural geography.

Outstanding Business Achievement

Apr 25, 2012 1:00 am

Five entrepreneurial students were recognised by the Principal (two from GeoSciences) for their outstanding business achievements. The students—Kanika Bansal, Maria Hillenkamp, Robert Trigwell, Paul Brennan, and Roland Partridge—have all won awards this year for their new business ideas and ventures.

Read More:

• "5 Students Recognised by University of Edinburgh Principal for Outstanding Business Achievements"