A selection of recent accomplishments from around our School drawn from the Disciplines of Botany, Geography, Geology, Zoology, Centre for the Environment, and the Trinity Centre for Biodiversity Research.
Oxygenation of the Archean atmosphere: New paleosol constraints from eastern India
Quentin Crowley, Ussher Assistant Professor in Isotope Analysis and the Environment in the School of Natural Sciences at Trinity, is senior author of a paper published in the world's top-ranked Geology journal, Geology. Working with Ph.D. student Kyle Heron, Professors Joydip Mukhopadhyay and Gautam Ghosh and other colleagues from Presidency University in Kolkata, India, their research found evidence for chemical weathering of rocks leading to soil formation that occurred in the presence of oxygen at least 3.02 billion years ago. Such substantial levels of oxygen could only have been produced by organisms capable of oxygenic photosynthesis. The early Earth was very different to what we see today. Our planet's early atmosphere was rich in methane and carbon dioxide and had only very low levels of oxygen. The widely accepted model for evolution of the atmosphere states that oxygen levels did not appreciably rise until about 2.4 billion years ago. This 'Great Oxidation Event' event enriched the atmosphere and oceans with oxygen, and heralded one of the biggest shifts in evolutionary history. Micro-organisms were certainly present before 3.0 billion years ago but they were not likely capable of producing oxygen by photosynthesis. Up until very recently however, it has been unclear if any oxygenation events occurred prior to the Great Oxidation Event and the argument for an evolutionary capability of photosynthesis has largely been based on the first signs of an oxygen build-up in the atmosphere and oceans.
Professor Crowley concluded: "Our research gives further credence to the notion of early and short-lived atmospheric oxygenation. This particular example is the oldest known example of oxidative weathering from a terrestrial environment, occurring about 600 million years before the Great Oxidation Event that laid the foundations for the evolution of complex life."
Oxygenation of the Archean atmosphere: New paleosol constraints from eastern India. 2014. Geology. Joydip Mukhopadhyay, Quentin G. Crowley*, Sampa Ghosh, Gautam Ghosh, Kalyan Chakrabarti, Brundaban Misra, Kyle Heron, Sankar Bose. DOI
Photos are available at: https://www.dropbox.com/sh/3lykgod3rggsjv2/AAD_2JMksTIUXu0A74Gyhb0ia?dl=0
OXYGENATION SYMOPSIUM: Quentin Crowley recently hosted a symposium on this theme, which was funded by the Irish Research Council, with a contribution from the School's research fund.
Breakthroughs in Understanding Grassland Ecosystems on a Global Scale
Fertiliser reduces plant diversity and can increase variability in grassland production, but in fertilized grasslands grazers help enhance diversity by ensuring dominant species don't steal all the sunlight. In two globally collaborative studies, published in Nature reporting the effects of fertilization and grazing on plant diversity and stability of grassland production, scientists used the Nutrient Network, or 'NutNet', to help predict how grasslands around the world will respond to a changing environment. Fertilisation reduces plant diversity as some species are able to take advantage of higher nutrient availability to grow quickly and shade out smaller or slower growing species. If grazers remove some of this extra biomass however the availability of light to smaller and slower growing species can be maintained. Fertilisation of grasslands also breaks down the link between plant diversity and stable biomass production so that higher diversity sites no longer provide more stable biomass production than lower diversity sites. NutNet is a grass-roots campaign supported by scientists who volunteer their time and resources. There are now 75 sites around the world that are run by more than 100 scientists. Professor Yvonne Buckley has been involved in NutNet since 2007 and will soon establish the first Irish site to add to NutNet's growing catchment area.
For more information please contact Yvonne Buckley email@example.com.
Hautier et al. In press. Eutrophication weakens stabilizing effects of diversity in natural grasslands. Nature. Available Online doi
Borer et al. In press. Herbivores and nutrients control grassland plant diversity via light limitation. Nature. Available Online doi
Ascaris, a parasite of global significance but why so neglected?
“Ascaris the neglected parasite” by Professor Celia Holland, is a call to arms for renewed research effort into ascariasis. This disease has been described by Peter Hotez, the guru of neglected tropical diseases (NTDs), as the ultimate NTD owing to its devastating impact on child health and the general lack of awareness of its true global importance. As a soil transmitted parasite, it results in chronic morbidity and presents an enormous challenge in regions of the world dominated by inadequate sanitation and poverty. The lack of a rodent animal model, in which the parasite completes its life cycle in a manner similar to humans, is an undoubted disadvantage as is the declining numbers off investigators that make Ascaris their focus. Prof Holland edited this book by drawing chapters from the World’s experts. It provides a blueprint of how a single parasite entity can engender interest in basic biology, clinical science, veterinary science, public health and epidemiology. One particular strength of the book is the elegant illustration of how quantitative biology can contribute to public health policy.
Holland, C.V. 2013. Ascaris: The Neglected Parasite. Academic Press. ISBN 978-0123969781
Informing Food Futures through CONSENSUS
Food security is an issue of global concern. However, solutions are traditionally focused on agricultural intensification, which leads to environmental, social and economic challenges. Yet, the other side of the food equation, the practice of eating, remains understudied. Trinity Geographers Prof. Anna Davies, Drs. Laura Devaney and Ruth Doyle recently completed a workpackage in the CONSENSUS project which aimed to rebalance the food futures debate. They designed and implemented novel co-design experiments to think through the question of eating more sustainably in the future. Key actors along the length of the food chain from public, private and civil society sectors were brought together to develop alternative scenarios for more sustainable food consumption. Following the publication of this work in Eurochoices (Davies, 2013), Prof. Davies was invited to participate in an OECD workshop in Paris on long-term scenarios for food and agriculture, presenting on ‘Challenges in food consumption practices towards 2050’. This workshop will culminate in a final report on policy choices for feeding the world of tomorrow, highlighting the centrality of the CONSENSUS research findings in global food and agricultural debates.
Davies, A.R. (2013) Food Futures: Co-designing Sustainable Eating Practices for 2050, Eurochoices. Summer 2013, vol. 12 (2), 4-11 doi
Forests Buffer the Effects of Climate Change on Plants
Collaborative international research involving Daniel Kelly, Fraser Mitchell and Miles Newman with researchers in Europe and the US scientists has shown that cool forest microclimates limit the effects of climate change on plants beneath the canopy. The work, published in the Proceedings of the National Academy of Sciences shows that species that are better adapted to relatively warm temperatures are less dominant in these environments. An unprecedented 1400 vegetation surveys from European and North-American ancient deciduous forests were compiled. This revealed that ‘warm-adapted’ species, such as common ivy, have become considerably more common than they were 35 years ago, but under the forest canopy cooler temperatures are limiting their spread. It is thus recommended that forests should be preserved as safe refuges for cold-adapted plants that are struggling in a warmer world. It is interesting to note that the Irish data contributed to this international investigation provide the strongest support for the overall conclusion that dense forest canopies damped the impact of global warming. This implies that the flora in Irish woodland is most vulnerable to the impacts of global warming if the tree canopy cover is not maintained. The principal threat to maintaining canopy cover is the inability of trees to generate due to high grazing pressure and this has been identified as a significant issue in woodland across the state.
De Freene, P. et al. 2013. Microclimate moderates plant responses to macroclimate warming. Proc Nat Acad Sci 110(46) pp 18561-18565. doi
Time is in the eye of the beholder
An international collaboration led by Dr Andrew Jackson and PhD student Kevin Healy including researchers from the University of Edinburgh and the University of St. Andrews has shown that animals’ ability to perceive time is linked to their pace of life. The study which was published in the leading international journal Animal Behaviour, showed that small-bodied animals with fast metabolic rates, such as some birds, perceive more information in a unit of time, hence experiencing time more slowly than large bodied animals with slow metabolic rates, such as large turtles. The researchers took advantage of this phenomenon to explain the observed variation in time perception across a broad range of animals, showing that animals that would be expected to be agile possess the most refined ability to see time at high resolutions.
Healy, K., McNally, L., Ruxton, G.D., Cooper, N. & Jackson, A.L. 2013. Metabolic rate and body size linked with perception of temporal information. Animal Behaviour, 86(4), 685-696 doi
Effects of energy crops on biodiversity and ecosystem service
Recent research as part of the SIMBIOSYS project, led by Jane Stout in the School of Natural Sciences and Trinity Centre for Biodiversity Research, has quantified the effects of growing bioenergy crops on biodiversity and ecosystem services in Ireland. PhD student, Jesko Zimmermann and Prof Mike Jones, in their recent paper in Global Change Biology Bioenergy, showed that even just two years after planting Miscanthus (a fast growing perennial grass grown for biofuel), a significant amount of carbon was already sequestered into soils. Furthermore, contrary to expectation, planting Miscanthus did not lead to significant losses in existing soil organic carbon stocks. Another PhD student, Dara Stanley, working with Jane Stout, investigated the effects of energy crops on pollinators and pollination and found that exclusion of pollinators from oilseed rape resulted in approximately 30% decrease in seed number and weight, equivalent to nearly €4 million per annum (published in Journal of Insect Conservation). Furthermore, Dara’s work showed that a wide range of pollinating insects use bioenergy fields (published in Journal of Applied Ecology) and that bees from more than 800 bumblebee colonies are attracted to individual oilseed rape fields (published in PLoS ONE).
Geology at the sub-microscopic scale
At the atomic level, the behaviour of chemical elements in solid matter is governed by the exact structure of the surrounding crystal. The quantification of these effects is at the forefront of geochemical research, to which TCD's Geology PIs are contributing with recent publications. Dr. Quentin Crowley was part of a team that demonstrated, for the first time, how the apparent age of zircon from highly deformed rocks can be affected by distortion of crystal lattice structures. Meanwhile, Prof. Balz Kamber and his PhD student Kirk Ross published the first empirical test of the widely used crystal lattice strain model for incorporation of the energy critical rare earth elements into pyroxene. Finally, Dr. David Chew and colleagues developed a new analytical approach to determine the chlorine content of apatite, which exerts critical control over the temperature at which fission tracks are erased. Collectively, these contributions demonstrate the convergence of geochemistry and nanoscience.
MacDonald, J.M., Wheeler, J., Harley, S.L., Mariani, E., Goodenough, K.M., Crowley, Q., Tatham, D. (2013). Lattice distortion in a zircon population and its effects on trace element mobility and U-Th-Pb isotope systematics: examples from the Lewisian Gneiss Complex, northwest Scotland, Contributions to Mineralogy and Petrology, 166, 21-41.
Ross, K., Kamber, B.S. and McDonald, A. M. (2013): An empirical test of the crystal lattice strain model for rare earth element partitioning into clinopyroxene. Chemical Geology, 340, 139-150.
Chew, D.M., Donelick, R.A., Donelick, M.B., Kamber, B.S., and Stock, M.J. (2013): Apatite chlorine concentration measurements by LA-ICPMS. Geostandards and Geoanalytical Research. doi