Awards - Round 7

The AFI Moderating Panel met on 30th March 2005 to evaluate the 26 full applications that were received in AFI Round 7. Five awards were made; details are as given below. The Panel also approved the support of the two additional applications submitted under the Collaborative Gearing Scheme.

Awards are listed in alphabetical order of Principal Investigator surname.

Awarded under the Collaborative Gearing Scheme (CGS)


Abstracts

(descriptions as supplied by the proposers, in response to a request by NERC for a summary 'in a style that would be accessible to an interested 14 year old')

Dr Peter Clarke, School of Civil Engineering & Geosciences, University of Newcastle upon Tyne
Dr Matthew King, School of Civil Engineering & Geosciences, University of Newcastle
Dr Keith Nicholls, Physical Sciences Division, British Antarctic Survey (NERC)

"Improved tide modelling for the Filchner-Ronne and Larsen C ice shelves through GPS data assimilation" [AFI7/22]

Some of the largest ocean tides in the world are found along the eastern coast of the Antarctic Peninsula and southern extent of the Filchner-Ronne ice shelf (FRIS), where the peak-to-peak tidal range can exceed 7 m. At present, however, our knowledge of the tides under these ice shelves is the most limited of any comparably-sized region on Earth. Mis-modelled ocean tides and ocean tide loading propagate into satellite-based measurements such as time-variable gravimetry (GRACE) and altimetry (e.g., ICESat), with present tidal model uncertainties suggesting possible biases well above the measurement noise of these instruments. Recent exciting measurements have also demonstrated large, tidally-driven modulations of ice shelf flow near the Rutford Ice Stream, similar in appearance to those previously identified on the Brunt Ice Shelf over 1000 km away, suggesting such modulations may be widespread features and that ice shelves may play a larger role in ice stream flow modulations than previously thought. We propose to study the three dimensional tidal dynamics of the major Weddell Sea ice shelves, namely the FRIS and Larsen C ice shelves, through direct GPS measurements and assimilation into an Antarctic numerical tide model. Regional-scale validations of the improved numerical tide model will be undertaken using onshore GPS measurements of tidal loading. Our results will significantly reduce the systematic error component in geodetic data (e.g. GRACE, Cryosat, GPS) used for key studies in post-glacial rebound, ice shelf thinning and ice sheet mass balance, and improve understanding of the intriguing tidal modulations of ice flow and their driving mechanism(s).

Professor Chris Hawkesworth, Department of Earth Sciences, University of Bristol
Dr Phil Leat, Geological Sciences Division, British Antarctic Survey (NERC)
Dr Tony Kemp, Department of Earth Sciences, University of Bristol
Dr Ian Millar, British Geological Survey (NERC)

"The age structure, origins and evolution of the Antarctic continent: new insights from detrital zircons" [AFI7/03]

There are two strands to this project: one on the evolution of the Earth's continental crust; the other on the geological evolution of the continental mass of Antarctica.

The continental crust is unique to the Earth Recent developments make it possible now to tackle fundamental questions about its origins and evolution. Such questions include: when did the rocks of the continents form? Were there periods when lots of igneous rocks were generated and other periods when fewer rocks formed, and why might that be? To what extent did these igneous rocks represent new continental crust, or were they derived by remelting older crustal rocks? In what tectonic settings was the continental crust generated, and did those settings change in different periods of Earth's history as, for example, between periods of rapid and slow crustal growth?

Antarctica is a large continent, representing almost 10% of the present continental mass on the Earth and yet, even in summer, only 2% of its rocks outcrop through the ice. Thus, (a) its geology is extremely difficult to study and (b) we don't know how its geological history differs from that of the other continents.

Both these topics, however, can now be addressed by detailed studies of the mineral zircon. Zircons occur as tiny crystal in most crustal rocks. They are very robust and are able to survive repeated episodes of erosion and sedimentation, even remelting and the generation of new igneous rocks. They contain growth zones that can be dated precisely, using U-Pb isotopes, and so they provide an unparalleled time series of changing magmatic conditions that can now be determined using hafnium and oxygen isotope ratio distributionss and trace element abundances. All these analyses are performed in situ, using ion beams or lasers, and the coupling of hafnium and oxygen isotopes can uniquely reveal whether even the individual growth bands in a zircon crystallised from a juvenile magma during crustal generation, or from a magma derived by reworking of pre-existing crustal rocks. Moreover, the trace element abundances in zircons can be used to distinguish broadly between those that crystallized from magmas generated within plate settings linked to deep-seated plumes, on the one hand, and those generated in subduction-related settings. The key here is being able to assess how much new continental crust was generated in response to deep-seated thermal disturbances, reflected in mantle plumes, or in response to shallow tectonic processes manifest in subduction zones, and how that balance changed with time.

Other studies have established that the distribution of ages from zircons in sediments is more representative of the rocks in their source regions than the rocks presently preserved on the Earth's surface. Thus, zircons from the glacial sediments around the edge of Antarctica offer an exceptional way to determine the ages of the igneous and metamorphic events recorded in the surface geology of this continent. This project will therefore date and analyse the respective hafnium and oxygen isotope ratio distributions and trace elements abundances in zircons, from those of late Precambrian age to those of Recent sediments, for the purposes of (a) providing new insight into the geological history of Antarctica; (b) tackling the larger questions concerning the generation of the continental crust identified above.

Professor David Hopkins, School of Biological and Environmental Sciences, University of Stirling
Professor Tony O'Donnell, School of Biology, University of Newcastle
Dr Kevin Newsham, Biological Sciences Division, British Antarctic Survey (NERC)
Dr Steven Rushton, School of Biology, University of Newcastle

"Microbial diversity in Antarctic soils" [AFI7/05]

Antarctica is the most southerly continent and it covers the south pole. Most of Antarctica is covered by ice, but in many places around the edges of the continent, and on many of the islands in the ocean around Antarctica, there is some ice-free land. This ice-free land includes parts of the South Orkney Islands (including the British Antarctic Survey's base at Signy Island), the South Shetland Islands, Adelaide Island (including the British Antarctic Survey's base at Rothera), and Alexander Island (including the British Antarctic Survey's station at Fossil Bluff). These places are all in the part of Antarctica directly to the south of South America and are going to be sites used in this research project. The sites cover a distance of about 1600 km, stretching from about 61°S (Signy) to 72°S (Fossil Bluff) and, with increasing distance to the south, the conditions become colder and drier; this has an important effect on the numbers, the different types and the activities, of the organisms that live on the land. These organisms include some plants, which become very rare and eventually disappear in the south, and microorganisms (including bacteria and fungi) living in the soil. The aim of this research project is to determine which organisms live in the soils of the different sites; how they live together in the different communities, and how they are affected by changing environmental factors such as temperature and the availability of liquid water. Knowing how the organisms are affected by changing environmental factors is important ,because Antarctica in general and especially the part of Antarctica where this project will be based, is responding fast to climate changes and is therefore an important indicator of change for the rest of the world.

Dr Ezio Rosato, Department of Biology, University of Leicester
Dr Edward Gaten, Department of Biology, University of Leicester
Professor Charalambos Kyriacou, Department of Genetics, University of Leicester
Dr Geraint Tarling, Biological Sciences Division, British Antarctic Survey (NERC)
Dr Rachael Shreeve, Biological Sciences Division, British Antarctic Survey (NERC)

"Gene function in Antarctic krill: determining the role of clock-genes in synchronised behavioural patters" [AFI7/06]

Antarctic krill form an important part of the oceanic ecosystem, acting as predators on plankton and as a food source for a variety of animals, including fish, sea birds and aquatic mammals. They migrate in a predictable manner each day, moving to the surface at night to feed and to greater depths during the day, to avoid visually guided predators. Krill also synchronise their spawning and moulting cycles to maximise reproductive success. It is not known how these cycles are controlled, but it is likely that they are regulated by 'clock' genes.

The circadian clock is an inbuilt mechanism by which the body controls many aspects of behaviour and physiology that oscillate with a 24-hour period, including the sleep-wake cycle, metabolic functions, and activity rhythms. The molecular basis of these cycles was originally described in fruit flies but has since been demonstrated in all animals investigated thus far. Interestingly, the circadian clock maintains the same general design but with remarkable species-specific differences. In additional to the circadian timekeeper, other clock mechanisms exist that control different types of periodicity, such as inter-tidal and lunar cycles, although their molecular architecture is still unknown.

The aim of this project is to describe, for the first time, how daily migrations and monthly spawning-moulting cycles of krill are controlled by clock genes. This will involve a series of behavioural observations, to describe locomotor activity under controlled conditions, and molecular investigations to identify the clock genes associated with the daily and monthly rhythmic phenotypes and their pattern of expression.

It has recently been shown that the abundance of krill has dramatically decreased in the Antarctic Ocean over the last 80 years and that this decline is correlated with a reduction in the extent of the sea ice due to global warming. In view of the importance of the species and the apparent threat from changes in climate, it is necessary that we fully understand krill behaviour so that we can monitor how they adapt to climatic changes. In particular, regular recruitment to the stock is necessary to maintain population levels, so an understanding of the reproductive cycle is essential.

In our work, we will use both standard and state-of-the-art methodologies and create new resources that we will make available to the scientific community. It is likely that other pelagic crustaceans have close sequence similarity with homologous krill genes. This will enable others to build on our work, both in the pursuit of scientific aims and also in relation to the farming industry.

Professor Martin Siegert, School of Geographical Sciences, University of Bristol
Dr Andy Smith, Physical Sciences Division, British Antarctic Survey (NERC)
Mr Hugh Corr, Physical Sciences Division, British Antarctic Survey (NERC)
Dr Richard Hindmarsh, Physical Sciences Division, British Antarctic Survey (NERC)
Dr John Woodward, Geography and Environmental Management, Northumbria University

"Geophysical exploration of a West Antarctic subglacial lake" [AFI7/02]

Antarctic subglacial lakes are liquid bodies of water located in topographical hollows beneath the ice sheets of Antarctica. They have attracted considerable scientific interest over the last ten years as they are expected to contain unique microbial life forms and detailed records of past climate change. Examination of these contents requires scientists to penetrate into a lake, and measure and sample the lake water and sediment. No lake has yet to be explored in this way, however. This form of direct analysis can only take place once a lake has been characterised fully by geophysical methods (to uncover the morphology of the ice base and the water depth of the lakes).

Of the 145 known subglacial lakes in Antarctica, none have been measured to the level required for meaningful direct analyses to take place. We propose to undertake a comprehensive geophysical exploration of a 10km long subglacial lake in West Antarctica, near the Ellsworth Mountains, named Subglacial Lake Ellsworth. The result of the project will be the first fully characterised subglacial lake environment and the establishment of a candidate for future direct exploration.

Data analysis and modelling will be undertaken at the University of Bristol, the British Antarctic Survey and Northumbria University.

Ice thickness will be determined from ice-penetrating radar; water depths will be found using seismic exploration, and ice flow and accumulation will be obtained from direct surface measurements. A series of numerical models will be used to understand the history of the lakes, the flow of ice across the lake, and the circulation of water within the lake.

Data visualisation will be undertaken in conjunction with Dr. Martin Jakobsson (collaborator).

Following this project, the next step will be to send a probe into Lake Ellsworth. A UK-led team has been assembled to plan such work (see www.ggy.bris.ac.uk/ellsworth) and take on what is arguably the most eagerly-awaited and high profile scientific project in the history of Antarctic science. Hence, the geophysical work that we propose here will be thought of, in years to come, as a hugely important first step towards the understanding of one of the greatest unexplored habitats on Earth.

Further information on individual CGS Awards:

Dr Rebecca Korb, Biological Sciences Division, British Antarctic Survey (NERC)
Dr Alex Cunningham, Department of Physics, University of Strathclyde

"Improving estimates of phytoplankton biomass around South Georgia" [CGS7/18]

Within BAS, the DYNAMOE group regularly surveys the waters surrounding the island of South Georgia as part of a long term monitoring programme. Phytoplankton blooms are a regular occurrence in these waters and may constitute some of the largest blooms in the open Southern Ocean. Such blooms support the high secondary production also found around the island. Understanding the spatial and temporal extent of blooms will be an essential component to understanding South Georgia's food web. Estimates of phytoplankton biomass are made through a combination of both shipboard and satellite data sets. Global algorithms for the retrieval of chlorophyll concentration from satellites under-predict the intensity of blooms in the Southern Ocean. The aim of this project is to improve the calibration of these algorithms through the study of in situ seawater composition and optical properties in the waters of South Georgia.

Dr David Barnes, Biological Sciences Division, British Antarctic Survey (NERC)
Professor Jeff Bale, School of Biosciences, University of Birmingham
Dr Roger Worland, Biological Sciences Division, British Antarctic Survey (NERC)

"The reproductive success of Antarctic marine invertebrates" [CGS7/19]

Organisms on land and in the intertidal face some similar, highly seasonal, problems such as intermittent food availability and ice. Other factors such as cold, desiccation, osmotic stress and iceberg disturbance, strongly contrast in their effects on animals across these zones. Frequently the interface is denuded of life, although a variety of taxa including springtails, mites, gastropods and even some sessile groups can be either resident or ephemeral visitors. This project will investigate the survival and life history strategies of interface organisms, by selecting a number of different species to study on a detailed, comparative basis. The 2/3 day shore collections at South Georgia and Signy Island will enable comparison of a Peninsula site (Rothera) with one in the sub-Antarctic (South Georgia) and maritime Antarctic (Signy).