Research Projects at Lowtex

1. Greening of retreating glaciers: storage versus export of autochthonous organic matter
2. Automated biogeochemical sensing of icy ecosystems
3. Biogenic production of climatic amplifiers under ice
4. Impact of iceberg sediment release to the Southern Ocean to CO2 drawdown
5. Direct measurement and sampling of Subglacial Lake Ellsworth: a multidisciplinary investigation of life in extreme environments and ice sheet history
6. Cryo-Egg: enabling wireless communications for a deep subglacial application
7. Investigating meltwater flow beneath the Greenland Ice Sheet using a multi-tracer approach

1. Greening of retreating glaciers: storage versus export of autochthonous organic matter

Funder - NERC
Value - 418,242
Dates - February 2009 to January 2012
Associated staff - Alexandre Anesio (PI), Martyn Tranter (Co-I), Jemma Wadham (Co-I) and Jon Telling (PDRA).

Glaciers are vast reservoirs of biological cells and other debris. Melting of the ice surface promotes increased levels of microbial activity via the creation of unique life-habitats (e.g. cryoconite holes). Colonisation of these niches subsequently leads to further darkening of the ice surface. The result is enhanced absorption of solar radiation, promoting further melt and providing yet more water for microorganisms, which are then dispersed to other parts of the ice surface. This dispersal also transfers the microbes, organic matter and debris to adjacent ecosystems, including the glacier forefields, the glacier bed and shallow marine environments. We hypothesise that glaciers become increasingly biological as they decay, and that glacier wastage is, in part, a biologically-mediated process that initiates ecological succession long before the ice has disappeared.

This project aims to quantify these biological effects on glacier mass wastage by examining the surfaces of retreating Arctic valley glaciers, and to determine fluxes and quality of organic matter (OM) exported to downstream environments. In particular, we aim to determine the importance of positive net primary production (i.e. autochthonously produced organic carbon) in promoting organic matter (OM) accumulation (demonstrated under our previous NERC grant NE/D007321/1), ice surface darkening and OM export downstream. We will also quantify allochthonous carbon deposition and melt out, and consider its interaction with the autochthonous carbon during biological (respiration) and physical (fluvial) processes of removal. In doing so, we aim to produce the first quantification and characterisation of bio-physical effects on ice mass wastage during deglaciation.

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2. Automated biogeochemical sensing of icy ecosystems

Funder - EPSRC
Value - 566,141
Dates - January 2006 to January 2011
Associated staff - Jemma Wadham (PI) and Liz Bagshaw (PDRA).

Ice-bound ecosystems remain the least explored sector of the cold biosphere, yet are now known to be a viable habitat for extremophile microbial life. They represent the closest earthly analogue for life on other icy planetary bodies, and were potential refugia for life during past global glaciations. In comparison to the deep oceans, for which remotely operated vehicles and specialist instrumentation have been developed, almost no specialized chemical/biosensors exist for use in icy ecosystems. In such physically remote settings, extreme cold, desiccation, high radiation, high pressure and physical abrasion by meltwater/ice are common environmental stresses. As a consequence, most biogeochemical investigations to date have relied on manual sampling of meltwaters, giving a small number of temporally discrete measurements. Such sampling methods yield limited information and are inappropriate for investigating more remote sub-surface environments, such as subglacial lakes. Significant innovation in the field of chemical/biosensor development is essential for temporal/spatial variability in microbial activity in the cryosphere to be understood, and in order to engage fully in the future exploration of Antarctic subglacial lakes and sub-ice water bodies on other planets (e.g. Mars, Jovian moons).

This project aims to develop the first generation of chemical/biosensors for high resolution monitoring of the liquid water component of the cryosphere. This will enable quantum leaps in our understanding of life and life habitats in these extreme cold environments and will contribute to the sensor developmental component for the Lake Ellsworth Programme. The sensor testing site is a glacier, Engabreen (Norway), where environmental stresses common to a range of icy ecosystems are present. A unique aspect of this site is the exploitation of the Svartisen Subglacial Laboratory, which enables relatively straight-forward emplacement of sensors in the high stress sub-surface environment. This work will provide a platform for the future development of a larger research group focused on biogeochemical sensing of the cryosphere and the acquisition of further funding from a variety of sources.

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3. Biogenic production of climatic amplifiers under ice

Funder - NERC
Value - 445,342
Dates - October 2007 to October 2010

Associated staff - Jemma Wadham (PI), Ed Hornibrook (Co-I, Earth Sciences), Richard Pancost (Co-I, Chemistry), Martyn Tranter (Co-I) and Marek Stibal (PDRA).

This project aims to address a significant gap in our understanding of the Earth's global carbon cycle, namely carbon cycling in subglacial habitats. Ice covers between 11 to 18% of the Earth's surface during Quaternary glacial cycles and may have been even more widespread in ancient periods of the Earth's history such as the Neoproterozoic. In contrast to other parts of the Earth's biosphere, cycling of carbon compounds beneath glaciers and ice sheets is poorly understood, since these environments were believed to be devoid of life. Significant populations of microbes (107/ml) have recently been found in subglacial settings. Evidence shows that, as in other aqueous sedimentary environments, subglacial microbes are able to process inorganic and organic carbon forms over a spectrum of redox conditions, producing climatic amplifiers CO2 and CH4. Almost nothing is known about 1) the range of carbon compounds available to subglacial microbes, 2) the degree to which they can be microbially degraded and 3) the rates of degradation and the full spectrum of reaction products. This information is critical to understanding the global carbon cycle on Earth. The fate of some ~330 Pg of organic carbon during the advance of the Quaternary ice sheets over the boreal forest, for example, is unknown and is likely to depend fundamentally on microbial processes in subglacial environments.

Current models of Earth's global carbon cycle assume this carbon is "lost" from the Earth's system. The possibility that it is degraded by subglacial microbes to CO2 and CH4 has not been considered, despite there being potential to explain the millennial to century scale increases in atmospheric methane during Quaternary warm periods. Subglacial environments lacking a modern carbon supply may represent ideal model systems for Snowball Earth and icy life-habitats on other terrestrial planets (e.g. Mars and Jupiter moons, and may be used to propose life viability and biogeochemical processes in these more extreme systems.

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4. Impact of iceberg sediment release to the Southern Ocean to CO2 drawdown

Funder - Leverhulme Trust
Value - 162,370
Dates - October 2007 to October 2010
Associated staff - Martyn Tranter (PI), Rob Raiswell (Co-I, ), Andy Ridgwell (Co-I) and Ros De'Ath (PDRA).

Our overall aim is to produce a quantitative estimate of the importance oficebergs in modifying CO2 drawdown in the Southern Ocean. Specifically, we aim to:

a. Predict the spatial and temporal pattern of nutrient release into the Southern Ocean from icebergs, model the biogeochemical response to these inputs, and calculate the contribution to the modern carbon budget related to iceberg iron delivery.

b. Apply the model to the Last Glacial Maximum (LGM) to investigate to what degree changes in iceberg fluxes in this period could explain changes in atmospheric CO2.

c. Provide predictions of the role of icebergs in changing the biological productivity and atmospheric CO2 draw down in the Southern Ocean through sensitivity studies for future climate change scenarios.

We will complete the following five objectives to accomplish these aims:

a. To gather data necessary for input to the model to constrain the rate and location of iceberg discharge from the Antarctic Ice Sheet.

b. To develop an iceberg model to include a versatile sedimentation scheme that can model the spatial and temporal release of bioavailable iron to the surface ocean.

c. To use an ocean-atmosphere model to force the model for 3 times periods; the present day, the LGM and for future climate scenarios to predict the variation in iceberg melt and flow during these periods.

d. To assess the impact of the bioavailable iron sediment release from icebergs on the biogeochemistry of the surface ocean using an Earth System model including a detailed oceanic carbon cycle.

e. To run a dust model within the same Earth System Modelling (ESM) framework and calculate the relative impact of dust fertilisation of the oceans compared to that of icebergs.

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5. Direct measurement and sampling of Subglacial Lake Ellsworth: a multidisciplinary investigation of life in extreme environments and ice sheet history

Funder - NERC Consortium led by Martin Siegert (Edinburgh)
Value - 52,741
Dates - October 2009 to September 2014
Associated staff - Martyn Tranter (PI) and Jemma Wadham (Co-I).

The objectives of this work package are to compare the water chemistry of Lake Ellsworth with that of the incoming ice melt to determine the following aspects of the physical, chemical and biological properties of the lake:
a. the residence time of the water and the nature of circulation and stratification
b. the dominant geochemical processes,
c. the nature of biogeochemical reactions and, hence,
d. geochemical indicators of life.

Website - http://www.geos.ed.ac.uk/research/ellsworth/

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6. Cryo-Egg: enabling wireless communications for a deep subglacial application

Funder - NERC
Value - 190,000
Dates - Jul 2010 - Jun 2012

Associated staff - Jemma Wadham (PI), Steve Burrow (Co-I), Ian Craddock , Geoff Hilton, Bruce Drinkwater and Mike Kendall.

A dramatic shift in wireless systems capability is required over the next 5-10 years to widen data capture to the entire Earth's surface, and hence to reduce uncertainty in forecast modelling under future change scenarios. The basal regions of ice sheets represent just one example of several deep sub-surface environments which currently feature as "voids" in our knowledge of Earth system function since extreme conditions and inaccessibility often prevent the use of cabled sensors. There have been no wireless sensors developed for deep ice sheet environments, where there is a pressing need to improve understanding of future response to climate change and to determine the sustainability and function of life-habitats. This proposal aims to provide the first proof-of-concept evaluation of wireless communications technologies for a deep subglacial application, suitable for incorporation in a future autonomous sensing system ("Cryo-Egg"). A wide range of technology challenges are embodied within this extreme icy environment, making solutions applicable to many less extreme but equally remote sub-surface situations where rock, water and or ice are present (e.g. deep ocean, mines, rock boreholes, permafrost). Technologies developed will have numerous possibilities for future uptake by deep ice sheet drilling science campaigns, to include, the Lake Ellsworth Exploration Programme.

Cryo-egg project website

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7. Investigating meltwater flow beneath the Greenland Ice Sheet using a multi-tracer approach

Funder - NERC
Value - 720,000
Dates - Sep 2010 - Aug 2014
Associated staff - Jemma Wadham (PI), Steve Burrow (Co-I), Alun Hubbard (Co-I), Peter Nienow (Co-I) and Tony Payne (Co-I).

The Greenland Ice Sheet (GrIS) is the main reservoir of ice in the northern hemisphere capable of affecting sea level in the 21st Century. Repeat-airborne laser altimetry surveys now provide a relatively comprehensive picture of GrIS recent mass balance. However, a poor understanding of ice dynamics and, in particular the coupling between surface melt forcing and ice flow response, limits the degree to which accurate predictions of future mass balance are possible. Geodetic and satellite data indicate that this coupling does indeed occur and produces 50-400% seasonal speed-ups on land terminating sectors of the western-margin. Observations of rapid supraglacial lake (SGL) drainage through 1km of cold ice to the ice sheet bed, and coincident ice acceleration provide one possible process by which surface melt and ice flow coupling is achieved. The mechanisms by which meltwater flows at the ice sheet bed, however, are largely unknown: a reflection of the difficulty of applying conventional meltwater tracing techniques at ice sheet scale. This information is critical if the coupling between ice sheet dynamics and hydrology is to be fully constrained in ice sheet models used to predict future sea level rise. In the absence of this coupling, model predictions only provide lower limits to the potential contribution of the GrIS to sea level change. This proposal builds upon pilot work conducted by the PI and Co-Is in 2009, and will employ highly sensitive chemical and electronic tracing techniques to improve understanding of GrIS englacial and subglacial hydrology. It will enable new linkages to be established between basal hydrology and ice sheet dynamics, and will generate a unique dataset for future numerical modelling studies aimed at quantifying the future contribution of the GrIS to global sea level rise.

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