THEME 2 – TERRESTRIAL CARBON
Newsletter June 2011
Contents
 New Theme 2 Co-convenors
 SAGES Graduate School publication prizes
 SAGES the future
 Diary dates
 John Grace retirement conference
 New PhD studentships
 SAGES NERC small grant success – the stability of soil organic carbon
 Where Thor’s River and Ocean meet
 Looking at soils at microscopic scales
 Amazon basin research report
New Theme 2 Co-convenors: Kate Heal and Susan Waldron
With the retiral of John Grace in September 2010 (see below) we jointly volunteered to “co-convene”
Theme 2. The aim of this newsletter is to update you on news from Theme 2 members and SAGES
and to invite your input and comments on future activities for Theme 2. SAGES is still active, the
Graduate School is here to stay and there are small amounts of funding to support focussed
networking activities within and between themes and with other research pools. We look forward to
hearing your ideas for using this funding.
Kate Heal, The University of Edinburgh, [email protected]
Susan Waldron, University of Glasgow, [email protected]
SAGES Graduate School publication prizes
Annual prizes (including a £100 cheque) will be
awarded for the best publication in each of five
categories, as judged by the SAGES research
committee. For more information go to the
SAGES Graduate School Web Page.
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SAGES the future
Limited amounts of SAGES funding remain
available to support networking activities with
clear benefits to SAGES members. Funding
requests are considered through SAGES
ResComm. Please contact us if you wish to
discuss any funding ideas.
SAGES officially ends in ?? However, following
visits by SAGES ExCom and ResCom Chairs,
Martin Siegert and Trevor Hoey, to all SAGES
HEIs, SAGES is anticipated to continue with
limited administrative support. The Graduate
School will continue as it is open to all PhD
students supervised by SAGES members
across institutions.
Dates for your diary in 2011
 14-15 June, Micro Soil 2 Conference,
Dundee. Organised by Wilfrid Otten
(Abertay) with SAGES support. See:
http://simbios.abertay.ac.uk/index2.php
 20-22 June, IUCN Peatland Programme
Annual Conference, Stirling University.
SAGES Theme 2 Newsletter, June 2011
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22-24 August, CLAD (Carbon Landscapes
and Drainage) network Catchment
Monitoring workshop, www.clad.ac.uk
1-2 September, Human Soils Legacy
Conference, University of Stirling,
supported by SAGES.
?? SAGES Centre for Earth System
Dynamics (CESD) Open Day, Edinburgh.
Contact??
9-11 November, SAGES Graduate School
Retreat at The Burn.
TBA, SAGES international event in place
of annual meeting
John Grace in Brazil in the 1980s (Image:
Patrick Meir)
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John Grace retirement conference
Maurizo Mencuccini, The University of
Edinburgh
To mark the retirement of Prof. John Grace, a
conference
called
Forests
and
the
Environment was held at the University of
Bologna (Italy) on 18-19 April 2011. John
Grace’s illustrious and productive career has
spanned a wide range of scientific fields, and
he has contributed significantly to shaping our
views of the role of forest ecosystems in the
global C cycle, of their contribution to climate
change mitigation and of their susceptibility to
climate extremes. Four main themes, covering
the main areas of science where John worked
over the years were covered in the conference:
‘Plant water transport under climatic stress’,
‘The terrestrial carbon cycle and interactions
with the cycles of nitrogen and water’,
‘Biogeographical limits and species distribution’
and ‘Tropical forests and the environment’.
Over 70 scientists from Europe, USA, South
America and Australia took part in the
conference, in a relaxed and productive
atmosphere in a beautiful city, hosted by the
oldest European University (the University of
Bologna was founded in 1088, eight years
before the University of Oxford). A special
festschrift issue of the journal Plant Ecology
and Diversity (previously published as the
Botanical Journal of Scotland) dedicated to the
papers presented at the meeting will be
published later this year.
New PhD studentships
Several new PhD studentships researching
terrestrial carbon are starting. Funded by a
NERC CEH studentship, Fraser Leith began
research into “Carbon production and transport
in the peat-stream continuum” in October 2010,
supervised by Kerry Dinsmore and Mike Billett
(CEH) and Kate Heal. Antony Phin will begin
“Quantifying
the
impact
of
windfarm
development on peatlands for aquatic carbon
and nutrient fluxes” in September 2011, funded
by a SNH-SEPA studentship and supervised
by Kate Heal, Susan Waldron, Hugh Flowers
(University of Glasgow) and Andrew Coupar
(SNH). Professors Susan Waldron, Marian
Scott and Jop Cooper of Glasgow University
have been awarded a studentship under the
NERC/ACTF Programme of Analytical Science
and Technology, commencing in October for
3.5 years. This studentship will focus on the
development of sensor technology for the
continuous monitoring of dissolved organic
carbon concentrations.
SAGES NERC Small Grant success
Joanna Cloy, The University of Edinburgh
SAGES Theme 2 Newsletter, June 2011
Clare Wilson, University of Stirling
Clare Wilson and Joanna Cloy, both appointed
through SAGES, along with Margaret Graham
(Edinburgh University) have been awarded a
NERC Small Grant to “assess spatial variability
of carbon, iron and aluminium concentrations
in gleyed soils as a means of understanding
the stabilisation of soil organic carbon”. The
research has uniquely combined bulk and
microscale analyses of mineral-soil organic
carbon (SOC) interactions in gleyed soils from
Harwood Forest, north-east England. Total Fe
and Al concentrations and weakly and strongly
crystalline Fe/Al oxides and associated OM
fractions were determined in soil sampled from
two depths. Chemical characteristics of the OM
associated with Fe/Al oxides were analysed
using FT-IR spectroscopy. Thin sections
subjected to sequential selective dissolution
were analysed by micromorphological and
SEM-EDX techniques to map the dissolution of
Fe and Al and identify areas of weakly and
strongly crystalline Fe/Al oxides (see image).
Amorphous Fe oxide impregnation surrounding
and within the organic tissues of a partially
decomposed root (Image: Clare Wilson)
Results show that the distribution of Fe-oxide
was very strongly correlated with the presence
of OM. Fe was the dominant component of all
oxide features except those associated with
amorphous
organic
or
organo-mineral
groundmass KATE TO ASK JOANNA WHAT
THIS IS where Al oxides dominated. The
nature of OM and Fe-oxide association
changed with depth, with fewer ‘fresh’ OM
residues, and more frequent strongly
impregnated orthic Fe-oxide features AT
DEPTH? KATE TO CHECK WITH JOANNA
WHAT THIS MEANS FOR STABILITY OF
SOC? – MORE STABLE AT DEPTH?. Fe/C
ratios suggested that simple adsorption was
not solely responsible for SOC sequestration
by strongly crystalline Fe-oxide features. In
general, the OM associated with and
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preferentially adsorbed by Fe/Al-oxides was
chemically different from the OM associated
with weakly and strongly crystalline Fe/Aloxides. KATE TO CLARIFY WITH JOANNA
WHAT THIS MEANS AND TO COME UP
WITH END STATEMENT ABOUT STABILITY
OF SOC.
From 1st June Joanna will be a researcher at
Scottish Agricultural College working on nitrous
oxide emissions from agriculture.
Where Thor’s River and Ocean meet:
Land-ocean carbon interactions off the
Caithness coast
Francois Muller, University of Highlands and
islands, Thurso
Many chemical oceanographers will remember
being taught how estuaries and the mouths of
large rivers can act as filters, removing a large
proportion of terrestrially derived substances.
They may recall the pioneering work of
Sholkovitz and co-workers (1976, 1978)
describing the flocculation of soil derived,
humic substances and, even more significantly,
the removal of ~ 90% iron in the freshwaterseawater mixing zone. This work was carried
out at the University of Edinburgh using
freshwater from the Tay and small rivers in the
Borders and Dumfries & Galloway. Sholkovitz’
findings were borne out by later investigations
of some of the world’s major river estuaries.
And so it was that the global riverine inputs to
the oceans of carbon, iron, and many other
elements came to be calculated from ‘average
world river’ concentrations coupled with
‘typical’ estuarine removal rates. Since then,
further research in other land-ocean systems
has revealed some serious weaknesses in this
approach. At least one type of land-ocean
system completely challenges our view of
estuaries as flow-through flocculation reactors
and some of the best examples of this can be
found…in Scotland.
The Flow Country of northern Scotland
comprises flat bog-pool systems similar to
those found at other northern latitudes. It
contains a multitude of small, dissolved organic
matter (DOM)-rich rivers which link the
peatland carbon stores to the marine
environment. The rapid dilution of the river
discharge with the surrounding ocean waters
and the low particulate matter concentrations
encountered during mixing ensure that this
DOM stays dissolved, even under marine
conditions. The material (mostly humic
substances) is in fact comprised of suspended
colloids which remain stable, and so escape
the estuarine mixing zone and are exported to
the marine environment. One consequence of
this unexpected behaviour is that any DOM-
SAGES Theme 2 Newsletter, June 2011
bound iron is also able to escape. In nearshore waters in Thurso Bay, north Caithness,
about 100% of the initially dissolved iron is still
soluble under marine pH and salinity
conditions. We believe that the high pH of the
River Thurso ‘pre-conditions’ the highly
electrostatic humic molecules responsible for
iron transport, effectively stabilising them
against flocculation.
Further research is now needed to
address two main questions. First, to what
extent can these findings be extrapolated to
other, larger and globally more significant
sources of terrestrial carbon (North America,
Russia)? Despite differences in the extent of
humic flocculation in the estuaries of Scotland,
Canada, Finland or Russia, the material that is
ultimately exported to the coastal environment
is very similar, so much can be learned about
its behaviour by studying the small plumes of
north Caithness and Sutherland. Which brings
us to the second main unanswered question:
what is the fate of the terrestrial DOM in the
ocean? We haven’t even taken the first steps
towards answering this question, yet we have
good reasons to believe that iron may play an
important role. We think that iron (and possibly
manganese) redox chemistry may initiate
many of the transformations of the humic
component of DOM during transit from land to
ocean. Over the next few years, we aim to use
the River Thurso plume (see image) as a
natural laboratory for examining the role played
by colloidal iron in catalysing DOM
transformations. With predictions of an
increased flux of organic substances from
peatlands, an understanding of these
transformations
becomes
increasingly
important. See also: Batchelli, Muller, et al.
2010, Environmental Science & Technology 44,
8485-8490.
Surface foam line of terrestrial humic
substances off the mouth of the River Thurso
formed after heavy rainfall (Image: Francois
Muller)
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Looking at soils at microscopic scales
Wilfrid Otten, SIMBIOS, University of Abertay,
Dundee
There is increasing evidence that knowledge of
the micro-environment of soils holds
the key to a more precise prediction of soil
ecosystem functioning. The opaque nature of
soil and the inherent complexity of the
architecture have meant that only very limited
improvements have been made linking
variability to function. Increasingly the
availability of novel technologies makes it
possible to look at soils at microscopic scales
and to use mathematical models to analyse the
impact on larger scale processes. Part of the
contribution to the objectives of SAGES Theme
2 by the SIMBIOS Centre at the University of
Abertay, Dundee, is to unravel the importance
of microscopic heterogeneity in soil carbon
dynamics.
The SIMBIOS Centre has a first class Xray CT suite with two tomography systems
dedicated to environmental research that
allows us to non-destructively characterise the
soil environment (and most other porous media,
such as biochar) down to 2 µm resolution. This
revolutionizes the way soil is studied.
Internal structure of biochar created from
sycamore char (supplied by A. Craig and J.
Cook), Saran Sohi, UK Biochar Research
Centre.
We obtain novel insights into flow pathways in
soils and microbial niches which regulate many
soil processes. Routinely we quantify porosity,
pore connectivity, pore-size distribution and
pore surface area, and address questions
concerning which one of these affect carbon
dynamics and how variable they are across
soil types. For example, we have analysed
how the pore geometry is affected by soil
management - taking samples from long term
field trials and then using mathematical
modelling to demonstrate the impact of pore
connectivity on hydrological properties and on
biological invasion, including the colonization
SAGES Theme 2 Newsletter, June 2011
by fungi. Currently we collaborate with various
universities and institutes in France to extend
this work to analyse the effect of soil
heterogeneity on carbon dynamics.
A key task is to get quantitative data on
the spatial and temporal variation at
microscopic scales of the physical, biological
and chemical properties of soils. Current
advances in physical (e.g. X-ray CT), chemical
(e.g. micro-focus XRF or NANOSIMS) and
microbiological (e.g. FISH) techniques have
significantly enhanced our ability to quantify
soils at increasingly smaller scales. However
these modern techniques have been
developed
within
separate
disciplines,
hampering a holistic approach to the soil
system. Perhaps more important, opportunities
to apply these techniques simultaneously or
combine them with the help of mathematical
modelling and statistical techniques are being
overlooked.
Following
an
international
workshop on this topic 2 years ago, we have
made significant progress in the integration of
these techniques. In a collaborative NERCfunded project with Stirling University (Clare
Wilson), we are developing and testing
experimental protocols and statistical tools to
integrate physical (X-ray CT) and chemical
(SEM-EDX) techniques to characterise the soil
microhabitat. More recently we have started
collaborating with Bremen University to
combine 2D thin sectioning techniques with 3D
X-ray CT and to use FISH to characterise
microbial distributions within a heterogeneous
soil sample.
The X-ray CT facilities offer SAGES
people great opportunities for collaboration.
Examples are far ranging, from scanning of
core samples or aggregates from field trials, to
test hypotheses related to soil physical
properties and other porous materials. For
further information on our research, please visit
http://simbios.abertay.ac.uk/index2.php
or
contact Wilfred Otten ([email protected]).
Amazon basin research report
Patrick Meir, The University of Edinburgh
Our team has been focussing on several areas
of ecosystem science in past year. In a project
funded by NERC and the Gordon and Betty
Moore Foundation, we are using a soil
translocation study to examine the long term
impact of soil warming on the breakdown of
soil organic matter in Peru. The study covers
many types of tropical rain forest: it traverses
more than 3 km in altitude from the Andean
treeline to lowland Amazonia. Notably this is
the first study to focus on the role of soil
microbial biodiversity in constraining the
climate sensitivity of decomposition across a
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large tropical altitudinal transect. In a second
project funded by NERC, the focus is to
quantify nutrient constraints to leaf respiration
in Amazonian tropical forests. Canopy
respiration is a very large component of the
forest carbon cycle and is strongly
temperature-sensitive, but we know little of
how it varies across the Amazon basin, and in
relation to soil fertility, which itself varies
notably from the Andes to the Atlantic Ocean.
Finally, in a different kind of project, I have
recently led a transdisciplinary consortium of
UK and South American partners in a NERC/
DfID/ESRC-funded project under NERC’s
‘Ecosystem Services for Poverty Alleviation’
programme. This project has had capacitybuilding as its focus. A key objective has been
to bring together different experts to examine
the role Amazonian forests play in providing
services and goods that humanity uses, and
also to examine their vulnerability to changes
in climate and land use.
Measuring soil respiration using a Licor 1800
(Image: Patrick Meir)
All of this work requires close collaboration
with colleagues in the UK and internationally,
especially in South America, and we gladly
acknowledge the friendship and expert
collaboration that makes this work possible.
Our main SAGES partners are St. Andrews
University, who have a particularly strong role
in the soil biogeochemistry component of the
research in Peru. Indeed, Dr Yit Arn Teh at St.
Andrews leads his own very substantial
programme
of
work
in
this
area,
complementing and linking with the work done
by Edinburgh and other partners.
In the next Newsletter…
 The latest research on mechanisms for
aerobic
methane
production
from
terrestrial vegetation by Andy McLeod.
 Susan Waldron reports on research on oil
palm plantations in Malaysia.
SAGES Theme 2 Newsletter, June 2011
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