Research Strands

Research Strands
Fundamental Soil Science

Soil is a beautiful media and may of us have become inspired by the teaching and writings of Dr. E. A FitzPatrick (Fitz). Fitz was the first PhD student ever in the Department of Soil Science and he pioneered pedology at Aberdeen. His books have been translated throughout the world and his innovative approaches and observations serve all scholars well.

Pedology is still alive and active (so is Fitz). Today we think of pedology in an integrated approach with processes. Rannveig Guicharnaud completed her PhD a few years ago and she was focussing on the interface between the biological processes and the pedology of Andosols.

Rannveig says -

"Studying biological parameters of northern latitude soils is of importance because of their high capacity to sequester organic matter. A consequence of climate change and the resulting increasing temperatures in the Arctic may be the shift from such soils being carbon sinks to becoming unmanageable carbon sources. Despite the relative harshness of the climate and the limited growing season, Icelandic soils are productively when cultivated and there is evidence of the emergence of a warmer and wetter climate emerging.

A key issue will be a consideration of the impact of intensify cultivation on the soils, landscape and general environmental parameters. This thesis studied the effect of climate, land use, fertilisation and soil pedological properties on Icelandic soils overall biology".

"Icelandic agricultural soils proved to be biologically active at sub-zero temperatures. Soil respiration and enzymatic activity were temperature dependent but the soil microbial biomass carbon was not. Labile carbon governed soil respiration at sub-zero temperatures. At -10°C, the availability of labile carbon accounted for 88% of the fraction of labile C while it accounted for only 42% at above zero temperatures. Labile carbon also played a key role in soil enzymatic activities both under field and laboratory conditions in cultivated soils of Iceland. Activities in frozen soils were attributed to Icelandic soils physiochemical properties allowing forhe presence of un-frozen water films around soil particles despite a frozen bulk soil".

"There was evidence that fertilisation associated with different cultivation practices suppressed nitrogen mineralisation.  The soil microbial biomass carbon pool in Icelandic soil was large in comparison to both high and mid latitudes soils and reflected their high carbon sequestration rates related to their geographical location and pedological properties. When biological parameters were integrated  into the World Reference Base for soil resources (WRB)  Icelandic soil (Mollic Andosols, Histic Andosols, Histosols) separated clearly from Scottish (Dystric Cambisols and Umbric Podzols). Soil biological parameters complemented physical and chemical parameter used to characterise soils within the WRB".

"In the environment, Soil biological parameters in Icelandic cultivated soils varied more greatly than chemical ones. The low variability of chemical parameters was a result of their stability within cultivated soils. High variability of measured soil biological parameters was a reflection of their transient nature and hence susceptibility to changes in increased land use and climate. The way in which soils were sampled likewise affected variability of measurements. Bulking soils into one single sample to represent regions gave highly variable results.In light of these results, the best way of sampling Icelandic cultivated soils for assessment of their biological activity, would be systematic intensive sampling. When assessing soil chemical properties sampling might require less number of samples but bulking soils would not be recommended".

"According to results obtained in this study, Icelandic soils carbon pools will be affected by increasing temperatures in the Arctic. The sampling to assess this conclusion was validated and the techniques in the laboratory were transferrable to the field. While it has not been possible to directly predict the impact of such change, this thesis establishes the transfer of techniques and approaches towards developing long term monitoring of such significant environmental perturbations".

Environmental Microbiology

Professor Ken Killham has been our inspiration for both soil and environmental microbiology. Since 1995, Ken was Professor of Soil Science here at the University of Aberdeen and his vision and inspiration has been a foundation to the work that we conduct today. Ken's vision was an integrated approach that combined culturable, molecular and process microbiology and that was applicable to soils, sediments and aqueous systems. His incredible publication list includes terrestrial, atmospheric, marine, freshwater and indeed martian landscapes. Having supervised two hundred PhD students and scores of researchers we all acknowledege his labours in this discipline.

Those of us who have known Ken a while will remember the joy he had when Soil Ecology was published. For others this may have been their first exposure to soil biology and the book has been an underpining basis to may of our research ambitions.

In a living system the biomass size and diversity are key components to investigate. This helps us to understand the processes and the fluxes in this system. While we mainly work with soils, we also apply our techniques to sediments, freshwater and the marine environment.

While other groups in the Institute have developed and applied a suite of molecular approaches, we tend to focus on culture-based and process level approaches. Such methods are of tremendous value especially when we wish to integrate measured physicochemical parameters to biological responses. Much of our work considers the impact of perturbations and how responsive processes are.

When we studied the response of soil processes to nickel and copper deposition from metal smelting in the Kola peninsula, we found that while pollutant burdens were high, the soil had acclimated to such changes. Biomass carbon and transformation were still active but the proportion that had become metal tolerant had risen significantly.

Environmental Biotechnology

We use environmental biotechnological approaches for the diagnosis of analytes and where suitable for the mitigation of pollutants. Genuine environmental applications of immuno-assays and whole cell biosensors have been pioneered in the laboratory. Once again it is the integrated approach of working at the interface of many disciplines that gives a novel and genuine insight into the power of such tools. 

Bacteria modified with market gene technology can give a new insight into habitats and reveal the presence and the extent of pollutant doses. They may also indicate the nature of environmental perturbations and allow an insight into quantifation of key biochemical processes.

At AWE Aldermaston and several other sites in Europe we have qualtified the concentration of chemicals of concern in groundwater using microbial biosensors. More rapid than chemical approaches and allowing real time deployment and interpretation such method could reflect the future of environmental diagnostics. Used effectively these can yield information on bioavailability in the context both of toxicity and degradation. 

Alas, there is a limited range of genuine application of these technologies and we recently reviewed this in an article and said-

"There is a popular story, that the late, great George Best, his soccer days behind him, was interviewed lying in a bed in a penthouse suite in Las Vegas. Next to him was Miss World and they lay upon a blanket of money – the winnings from a successful night on the casino floor, whilst bottles of champagne and caviar littered the room.

The journalist coughed and said ‘‘George, where did it all go wrong?.’’

Indeed, the genuine environmental application of bioreporters has suffered a similar fate. George Best was an athlete, a footballer, a womanizer, philanderer, and party animal. He was undeniably all of these, but not at the same time. Whole cell bioreporters are analytical devices for detection, quantification, tools for hazard assessment and derived risk assessment and assays for assessing bioavailability. But as with George Best, these applications are neither mutual nor exclusive. The inherent advantage of these tools in terms of flexibility in turn is also their greatest weakness, in that the user must clearly understand and evaluate the role before addressing the application stage".

 

Environmental Toxicology

Polluted soils may pose a significant threat to target receptors: humans, ecology and controlled waters. The extent of this harm can be measured directly using a suite of biological assay or indirectly through the operation of risk assessment models.

We make use of both approaches and deal with each of these key receptors. Much of this work is conducted in former industrial sites where the soils are more typical of fill. But so too the work is conducted in genuine soils often exposed to diffuse rather than point source contaminants.

The key aspect is to define the source of the contamination (this includes the form and the speciation) and to consider the receptors that need to be protected. This could be very specific: such as a toddler or generic such as an ecosystem function. Then the significance lies in the connectivity of these two components by means of the pathway.

To best acheive this we need to have thorough techniques for chemical analysis to complement valid and relevant sampling approaches. In addition to sampling, analysing and risk assessing the soils, we need to consider the full extent of the other media that could represent both pathways and receptors.

Hazardous Chemicals - umauthorized wntry prohibited sign

Remediation Technologies

The group is uniquely placed in that we are able to transfer laboratory findings to the genuine field environment. Several of the group also work with Remedios an Environmental Technology company that pioneer the application of novel and sustainable technologies in the remediation of contaminated land.

Remediation technologies must be science led but be field applicable.This means that the focus must be on developing novelty in the way that techniques are delivered. We mainly focus on bioremediation but also consider other chemical and physical approaches for a suite of solutions. High replication and multi-factorial approches give confidence to the deployment of these approaches to real scenarios.

Today we are integrating the science with the process of decsion making by considering the steps that best justify remediation approaches. This is about meeting the targets in a cost effective and environmentally sustainable manner.