Awards - Round 9

The AFI Moderating Panel met on 1st April 2008 to evaluate the fourteen full applications that were submitted to Round 9 of AFI. Based on the Panel’s recommendations, NERC was able to award funding for six of the proposals; details are as given below. The Panel also approved (retrospectively) the support of six applications submitted under the Collaborative Gearing Scheme.

Awards are listed in alphabetical order of Principal Investigator's surname.

Awarded under the Collaborative Gearing Scheme (CGS)


Abstracts of awarded AFI Round 9 proposals

(Descriptions as supplied by the proposers, in response to a request by NERC for a summary 'in a style that could be publicised to a general audience')

Dr Angus Atkinson. Biological Sciences Division, British Antarctic Survey
Dr Eric Achterberg, National Oceanography Centre, University of Southampton
Dr Sophie Fielding, Biological Sciences Division, British Antarctic Survey

"The role of krill grazing in Southern Ocean nutrient cycles" [AFI9/07]

One of the major problems mankind is facing in this century is an increasing number and intensity of natural disasters (e.g. hurricanes, floods, melting ice sheets). Many of these disasters are indicators of global climatic changes related to the ever-increasing amount of CO2 humans release into the atmosphere. So far, a large proportion of these CO2 emissions has been absorbed by the oceans and tucked away for centuries, but to predict the future, we need to understand the mechanisms involved. This proposal tackles one possible mechanism within the Southern Ocean. We hypothesize that a small crustacean - Antarctic krill / helps the drawdown of carbon (C) from the atmosphere into the deep ocean.

Three facts about krill lead to this suggestion: Firstly, krill are very abundant, with a total mass greater than that of the human population. Secondly, krill have very high feeding rates and feed mainly on phytoplankton, the algae, which build their own organic C from the CO2 dissolved in the water. Thirdly, krill faeces sink as compact pellets towards the seafloor. Thus, krill mediate the carbon transition from small floating algae to large sinking faecal pellets, a process known as the "biological C pump". Unfortunately, it is slightly more complicated than this. With the sinking pellets, krill might also export other elements from the surface layer, e.g. iron (Fe) and silicon (Si) that are essential for the algae to grow and often in limiting concentrations.

Even though krill are a key species in the Southern Ocean food web and commercially fished for, little is known about their role in biogeochemical cycles. None of the essential processes has been measured before in detail, thus, we need more information to test our hypothesis:

  1. How much C, Si and Fe are in the krill faecal pellets?
  2. Do the elements dissolve out of the pellets before sinking to depth?
  3. Do krill accumulate Fe into their bodies?
  4. How much Fe and Si do krill release in dissolved form when feeding?

The last question is especially important, because a fast regeneration of particulate Fe into the dissolved form via krill might stimulate algal growth and therefore a further uptake of CO2.

Our plan is to tackle these questions during a cruise in the Southern Ocean. We will collect krill and incubate them onboard to measure the rates of pellet production and release of dissolved nutrients. We will sample their pellets from different water depths, to compare the total numbers and the content of C, Fe and Si. These measurements will be related to water column profiles of Fe and Si, both in dissolved form as nutrients and in particulate form in algal cells.

We will sample at a range of stations within different environments / some with lots of algae, others with few, some with sufficient Fe and Si, others with too little. This will enable us to make simple equations that relate the various rates in krill (see 4 questions above) to their available food and nutrient situation. With help of these equations, we can scale up the results from our sampling sites to answer our overall question: Do krill support the biological C pump by exporting C and recycling nutrients, or do they stop the pump by removing Fe and Si from surface water?

Our ship-time bid is for 11 days in the Scotia Sea during 2009/2010. To increase our seasonal and regional coverage, we will supplement the data set with a range of frozen samples from previous cruises.

Both measuring Fe and handling krill are non-trivial tasks; therefore the proposal combines expertise across two institutes, the British Antarctic Survey and the National Oceanography Centre Southampton. The scientists involved supply all the essential skills in locating, catching and experimenting with krill (Atkinson, Fielding, Schmidt); in trace metal clean work (Achterberg, Rijkenberg); in oceanography (Venables); and in marine chemistry (M Whitehouse).

Dr Mike Bentley, Department of Geography, University of Durham
Professor Stewart Freeman, Scottish Universities, Scottish Universities Environmental Research Centre
Dr Richard Hindmarsh, Physical Sciences Division, British Antarctic Survey
Dr Tibor Dunai, School of Geosciences, University of Edinburgh
Dr Andreas Vieli, Department of Geography, University of Durham

"Thinning history of the foundation-Thiel trough ice stream: A key control on deglaciation of the West Antarctic Ice Sheet, Weddell sea embayment" [AFI9/13]

The Antarctic ice sheet is the largest on earth and any instability is likely to dominate global sea level change. We therefore require models of the ice sheet to make more reliable and robust predictions of future change. One problem in meeting this challenge is the lack of past data on deglaciation with which to initialize and calibrate the models. This problem has been particularly acute in the Weddell Sea embayment and in particular its eastern part where the Foundation - Thiel Trough has been a principal drainage route for the West Antarctic Ice Sheet (WAIS), and its southern extension may be a potential location for future instability. We propose here an integrated field and modelling study that will exploit the opportunity of several emerging field datasets from a range of different disciplines, collect fresh data from a crucial location, and investigate past and future deglaciation using sophisticated ice sheet models. To understand the history of ice thinning and retreat along the trough we will adopt a dipstick approach to survey the Foundation Ice Stream, an upstream extension of the ice stream that occupied the trough during the last ice age. We will determine the thinning history of this Foundation- Thiel Trough Ice Stream from geomorphology and exposure age dating: techniques that have been used effectively to provide insight into ice sheet history in other regions of Antarctica. We will apply a 3D model incorporating significant recent theoretical advances - to the whole of the W AIS in order to understand the forcing mechanisms for the ice stream history we measure. We will go on to use this model to predict the likely future stability of the W AIS in terms of both long-term trajectory and any response to climate change scenarios, and in particular whether it will retreat further along the Foundation-Thiel Trough.

Professor Geoffrey Boulton, School of Geosciences, University of Edinburgh
Dr Andy Smith, Physical Sciences Division, British Antarctic Survey

"Hydraulics and sediment deformation beneath an ice stream: a multi-component geophysical AVO investigation" [AFI9/23]

Streams of fast-flowing ice (ice streams) play a major role in the movement of large ice sheets such as those of Greenland and Antarctica. Although they cover only a small part of the total ice sheet area; they discharge over 3/4 of the ice mass that flows into surrounding oceans. If the ice sheets were to decay rapidly under conditions of global warming, much of the net mass loss, and the resultant rise in sea level, would take place through the speeding up of ice streams. Geological evidence shows ice streams to have played similar roles in the ice sheets that covered much of North America and Eurasia during the last glacial period.

Ice streams flow quickly because of the low friction surface over which they flow. Recent research has shown in many, possibly the majority, of cases studied that this is because extensive areas of the bed are covered by sediment which deforms readily, and provides a rapidly-deforming, low friction carpet that eases ice stream movement. In order to deform under considerable ice thicknesses, the sediment needs to be unfrozen, with high internal water pressures that almost balance the pressure due to overlying ice. This water is derived from melting at the base of the ice sheet, and sometimes from water from the surface that percolates through the ice sheet. If the ice sheet is not to become buoyant and unstable due to water build up at its base, the water must drain through the ice sheet system and be discharged from its margin. A central unsolved problem in glaciology is to determine the water pressure gradient along this drainage pathway, which will determine the local water pressures and therefore the local friction and flow at the ice/bed interface.

Recent work on the Rutford Ice Stream of the West Antarctic Ice Sheet has revealed an excellent site for the study of this problem, where a deforming subglacial sediment carpet has been identified using seismic primary (P) waves that are able to recognize whether or not a subglacial sediment is deforming. We propose to extend this technique by using both P and S (shear) seismic waves that will permit us to increase the power to resolve small differences in deforming layer thickness, and to use a more sophisticated survey technique called AVO and a recent development of poro-elasticity theory to deduce a much wider range of subglacial conditions. Amongst these, the most important will be water pressure in the subglacial sediment, which will permit us to reconstruct the form of the subglacial "water table" which ultimately controls sediment deformation and basal friction. We will use the inferred hydraulic patterns to test theories of subglacial drainage.

Another important discovery at the Rushford has been the existence of "drumlins" (long ridges, streamlined in the direction of ice flow), which have also been shown to be made of deforming sediment, and which move in the direction of ice flow. Drumlins are widespread in areas of former glaciation, and particularly densely clustered along former ice streams. If drumlins are characteristics of a deforming glacier bed as has been suggested, and as is implied by the Rutford observations, they will provide a powerful means of understanding how the large scale dynamics of the bed of an ice sheet operates by studying the beds of Ice Age ice sheets that can be so readily observed over Eurasia and North America. An important part of our research therefore will be to use a radar system to image the form of the ice stream bed and the distribution of drumlins, to relate these to hydraulic conditions and deforming bed processes, and by studies in two field seasons (added to existing, earlier data from the same area), to monitor how the hydraulic and deforming bed system changes through time. We also hope to estimate the flux of water and sediment through the ice stream system, in order better to understand the role it plays in the rate of geomorphological and sedimentary change in this part of Antarctica.

Professor Neil Glasser , Institute of Geography and Earth Sciences, University of Wales, Aberystwyth
Professor John Smellie, Geological Sciences Division, British Antarctic Survey
Dr Jonathan Carrivick, School of Geography, University of Leeds
Professor Michael J Hambrey, Institute of Geography and Earth Sciences, University of Wales, Aberystwyth

"Glacial history of the NE Antarctic Peninsula region over centennial to millennial timescales" [AFI9/01]

When glaciers and ice sheets melt, they release large volumes of fresh water into the oceans. The release of fresh water into the oceans not only raises sea level but also influences deep sea circulation and therefore regional climate. On the Antarctic continent, the largest freshwater store on the planet, glaciers are buffered from the oceans by large ice shelves. These ice shelves form when glaciers reach sea level and spread out to form a floating or grounded shelf. Recent media coverage of the Twentieth Century ice shelf collapse has focused the world’s attention on this topic and it has been suggested that many ice shelves particularly around the Antarctic Peninsula, are now becoming unstable as a result of global temperature rise. Against this background, it is important that we understand the behaviour of Antarctic Glaciers and ice shelves in the past, present and future.

The aim of this project is therefore to reconstruct the outline and evolution of the Antarctic Peninsula Ice Sheet through the Quaternary Period (the last two million years). We will do this using a variety of different methods including mapping of glaciers and associated landforms from satellite imagery and in the field collecting samples of rock from glacial moraines for dating with cosmogenic isotope dating; and comparing our evidence on land to previous studies from offshore cores that record past fluctuations of the Antarctic Peninsula Ice Sheet.

Obtaining dates for the timing of periods of growth and decay of the Antarctic Peninsula Ice Sheet will enable us to reconstruct the former fluctuations of this ice mass and therefore to make predictions about its possible future behaviour. We will also be in a position to draw conclusions about whether or not the ice shelves surrounding the Antarctic Ice Sheet have collapsed in the past.

Dr Matt King, Civil Engineering and Geosciences, University of Newcastle
Dr Mike Bentley, Department of Geography, University of Durham
Dr Richard Hindmarsh, Physical Sciences Division, British Antarctic Survey
Professor Phil Moore, Civil Engineering and Geosciences, University of Newcastle
Dr D Lavallee, Civil Engineering and Geosciences, University of Newcastle
Dr Ed King, Physical Sciences Division, British Antarctic Survey

"Improved models of West Antarctic glacial isostatic adjustment through new crustal motion data" [AFI9/10]

This project addresses the current uncertainty in the present-day contribution of the West Antarctic Ice Sheet to global sea level rise. These estimates are primarily derived from space geodetic (altimetry or time-variable gravity) measurements, with time-variable gravity data from the Gravity Recovery and Climate Experiment (GRACE) satellite mission the only technique capable of determining ice mass balance for the entire ice sheet. Estimates of ice mass change from the total mass change (observed by GRACE) are, however, severely limited due to the large discrepancies between contemporary models of Antarctic glacial isostatic adjustment (GIA). Indeed, recent published estimates of ice mass change for West Antarctica are swamped by this uncertainty.

Global Positioning System (GPS) time series offer important constraints on GIA and, indeed, GPS have been installed in a few of the critical locations. However, the current network of GPS sites in West Antarctica, whilst useful in discriminating between major differences in contemporary GIA models, is too sparse to provide the constraints required to significantly reduce the GIA uncertainty in the GRACE signal for that a high spatial resolution of GPS sites is required. In particular, the southern Antarctic Peninsula Ronne Ice Shelf contains a very large GRACE signal, but the current GPS station density there is too sparse to unambiguously determine the origin of the gravity change. Further rock outcrops suitable for additional data collection are available in this region and installing new, more densely spaced, continuous sites would provide the required constraints. Here, we propose to develop improved models of West Antarctic GIA through newly collected long-term GPS data, thereby allowing us to compute new accurate and precise estimates of ice mass contributions to sea level rise from West Antarctica.

These results are of direct relevance to NERC's draft strategy (2007-2012) to expand on existing knowledge of the fundamental driving forces and feedbacks of the Earth system through prioritising plans to investigate how the cryosphere responds to global change.

Professor Cathryn Mitchell, Department of Electronic and Electrical Engineering, University of Bath
Dr Martin Jarvis, Physical Sciences Division, British Antarctic Survey
Dr Ivan Astin, Department of Electronic and Electrical Engineering, University of Bath

"Remote GPS measurements to improve SAR ice monitoring" [AFI9/18]

Space-borne synthetic aperture radar (SAR) observations can be used to measure structure and velocity within the Antarctic ice sheet. Most SAR missions to date have used L-band frequencies (1-2 GHz) but interest is now turning to lower-frequency P-band signals (around 430 MHz) because they have greater penetration of the ice. Both the University of Bath and BAS are currently involved in feasibility studies relating to P-band SAR design for future ESA satellites. P-band SARs in polar orbits such as the ESA BIOMASS satellite due to launch in 2014, have the potential to map out the three-dimensional structure of ice sheets. However, their signals will suffer from significant ionospheric effects inducing Faraday rotation, range defocusing, range delay and interferometric phase bias. The ionosphere must be taken into account in the system design but the necessary ionospheric measurements to do this do not currently exist. This project will deliver the measurements for the Antarctic region and lay the foundation for successful P-band SAR missions.

This project involves equipment development, fieldwork and analysis. The objective of the fieldwork is to deploy modified GPS receiving equipment that will for the first time take measurements of total electron content (TEC), plasma velocity and ionospheric scintillation at remote locations across the Antarctic. To achieve this, eight new GPS receivers will be deployed to undertake long-term measurements in the auroral and polar-cap regions over a two year period. Additional data from lower Antarctic latitudes will be provided by international partners. The measurements will be used to develop a multi-scale model of the Antarctic ionosphere. This model will be a critical input to SAR design that will minimize the impact on ice measurements for future satellite missions.

Further information on individual CGS Awards

Dr Jason Matthiopoulos, Department of Biology, Sea Mammal Research Unit, University of St Andrews
Dr Richard Phillips, Biological Sciences Division, British Antarctic Survey
Dr Phil Trathan, Biological Sciences Division, British Antarctic Survey

"Improving habitat preference models with information on the mechanisms of individual flight" [CGS8/30]

Determining the movement patterns and habitat preferences of apex predators such as albatrosses is integral to the development of individual-based approaches to modelling search behaviour, and hence the quantification of spatio-temporal variability in prey consumption and energy flow. This study will involve the simultaneous collection of location, activity and prey ingestion data from foraging black-browed albatrosses to test the efficacy of movement-based proxies of foraging behaviour, such as speed, track tortuosity and takeoff/landing rate. This information will greatly improve habitat preference models currently being developed jointly by the University of St Andrews and BAS. Data will also be used to estimate the contribution of gelatinous prey, such as salps, which are difficult to detect using conventional sampling techniques.

Dr Andy Hodson, Department of Geography, University of Sheffield
Dr David Pearce, Biological Sciences Division, British Antarctic Survey
Dr Kevin Newsham, Biological Sciences Division, British Antarctic Survey

"Biogeochemistry of the Mars Oasis ecosystem" [CGS9/31]

Rapid regional warming has led BAS researchers to develop a metagenomic data resource to characterise the various stages of ecosystem response to change. The proposed project will greatly enhance the utility of this core research effort by developing a complementary biogeochemical data resource necessary for a comprehensive interpretation of how Antarctic microbial communities respond to the environment. Particular attention will be given to organic and inorganic biogeochemistry of those flow paths that provide essential water for life in the Mars Oasis ecosystem. Thus, the important link between the physico – chemical conditions of a key field site and the activity of its resident microorganisms will be constrained using just a minor field programme and the collection of water, snow and sediment samples for detailed chemical analysis at Sheffield.

Dr Derek Vance, Department of Earth Sciences, University of Bristol
Dr Claus-Dieter Hillenbrand, Geological Sciences Division, British Antarctic Survey
Dr James Smith, Geological Sciences Division, British Antarctic Survey

"Neodymium isotopes in Southern Ocean water masses and deep-water sediments" [CGS9/32]

A knowledge of the history of Circumpolar Deep Water (CDW) upwelling is central to understanding the driving forces for West Antarctic Ice Sheet (WAIS) deglaciation, This proposal is part of a project that seeks to develop and apply neodymium (Nd) isotopes as a tracer of past CDW upwelling. Preliminary water column data from the Amundsen Sea shelf have demonstrated the distinct isotopic nature of deep water there. Here we seek to obtain open ocean water samples to confirm the CDW isotopic signal and to characterise its depth extent. We will also use the data to better characterise Southern Ocean sources to the global deep ocean circulation system, with applications in the use of Nd isotopes for the study of Atlantic meridional overturning.

Dr Adrian Glover, Zoology Department, Natural History Museum
Dr Katrin Linse, Biological Sciences Division, British Antarctic Survey

"Biodiversity and evolutionary origin of Antarctic polychaetes" [CGS9/33]

Polychaetes form one of the most abundant and biodiverse components of the Antarctic shelf and Southern Ocean deep-sea benthos. To date, there have been no comprehensive quantitative studies undertaken of both shelf and deep-water Southern Ocean polychaetes. Our aim is to investigate biodiversity levels in Southern Ocean polychaetes using the existing planned cruise BIOPEARL (JR 179), and to place these data in a global phylogenetic context to test hypotheses of the evolutionary origin of Antarctic polychaetes. We see it as essential to collect these baseline data for one of the most biodiverse faunal groups in a region subject to pronounced climate warming trends.

Dr Rebecca Korb, Biological Sciences Division, British Antarctic Survey
Dr Eric Achterberg, National Oceanography Centre, University of Southampton
Dr Tom Bibby, National Oceanography Centre, University of Southampton
Dr Mick Whitehouse, Biological Sciences Division, British Antarctic Survey
Dr Mark Moore, National Oceanography Centre, University of Southampton

"Iron availability and effects on phytoplankton communities in contrasting production regimes of the Scotia Sea: a seasonal perspective" [CGS9/34]

The availability of iron (Fe) limits primary productivity and the associated uptake of carbon over large areas of the Southern Ocean. Fe thus plays an important role in the carbon cycle. Whilst much of the Southern Ocean is characterised by High Nutrient, Low Chlorophyll (HNLC) water, there are areas that are highly productive and are naturally enriched with Fe. In general productivity in the Scotia Sea is high but particularly so downstream of the island of South Georgia. The annual phytoplankton bloom associated with the island is the largest in the open Southern Ocean and potentially one of the largest sinks of carbon. Such phytoplankton blooms are of enormous importance in terms of supporting the high secondary production of the region and thus are an important component of Scotia Sea foodwebs. However, there are few measurements of Fe availability or its role in regulating blooms in this productive sector of the Southern Ocean. The first major BAS cruise (JR161) of the Discovery 2010 programme provided a unique opportunity to map concentrations of Fe and phytoplankton communities in the Scotia Sea during the austral spring. At the beginning of the phytoplankton growing season (i.e. spring), standing stocks of phytoplankton are low and, both macro- and micro-nutrient availability is high. During the height of the bloom, in summer, concentrations of macro-nutrients such as silicic acid may become growth limiting and it is likely that Fe will also be depleted. Fe-poor waters will result in a shift in phytoplankton composition which in turn could have important consequences for secondary producers. Therefore an investigation of the availability of Fe and its affects on phytoplankton communities during the austral summer is critical to fully understand the role of Fe in the carbon cycle of the Scotia Sea. The work of our proposal complements the Discovery 2010 FOODWEBS programme in examining controls on primary production during different seasons.

Dr Dorothee Bakker, School of Environmental Sciences, University of East Anglia
Dr Angus Atkinson, Biological Sciences Division, British Antarctic Survey
Dr Nick Hardman-Mountford, Plymouth Marine Laboratory

"Quantifying carbon drawdown and seasonal uptake across a major Southern Ocean carbon sink" [CGS9/39]

The Southern Ocean is important for the earth’s climate, but lack of sampling here means that we know little of its role in mitigating the buildup of atmospheric CO2. Drawdown of CO2 into the ocean is driven by the difference in the partial pressure of CO2 (pCO2) between the atmosphere and the ocean. Novel pCO2 instruments have recently been fitted to the NERC fleet to measure this. After a first and successful CGS-funded field season (2006/2007) to tailor the system for use aboard James Clark Ross, we apply here to send Elizabeth Jones from the University of East Anglia (UEA) down south again, on cruise JR177. This is the main Discovery 2010 summer cruise, in Jan-Feb2008. We aim to: (a) compare the pCO2 system installed on the RRV James Clark Ross with an established UEA sensor, and (b) collect vertical profile data to quantify mechanisms of biological carbon uptake, thus supporting BAS core science objectives for this process cruise. nce our understanding of the cryosphere in Neogene time and our ability to forward model the effects of global change over the next few centuries.