Environmental Physiology

Research in environmental physiology is investigating the physiological and biochemical responses of organisms to their environment. Given the ever increasing impact of humans on the natural world, this topic area is of high importance.

Work led by Dr Sophie Fauset investigates patterns in leaf temperatures in tropical forest. Leaf temperatures are not the same as air temperatures since they depend on the local environmental conditions (e.g. light intensity, air temperature, humidity, wind speed), and particular characteristics of the leaves themselves, such as size and stomatal pores opening in high air temperatures. Different tree species exhibit different leaf temperature patterns, and temperatures can vary by as much as 18°C (Fauset et al. 2018). Working with the University of Sao Paulo, Sophie has shown leaf temperatures increase with both elevated air temperatures and increasing CO2, even when measured under the same environmental conditions as control plants (Fauset et al. 2019). This is important because it suggests that under climate change, leaf temperatures will increase more than expected purely from a rise in air temperatures. Recent funding success has led to new projects utilising thermal imaging to assess the response of whole forest canopies to a changing microenvironment. We will set up new measurements in the UK and Ghana, and combine our data with other researchers from Brazil, China, India, USA and Australia to examine large scale patterns.

Professor David Bilton is an expert on aquatic insect ecophysiology. His work has provided insights into why most species are rare (irrespective of human activity), highlighting the importance of thermal biology and metabolic plasticity in the extent to which species have expanded their ranges since the last ice age, as well as determining vulnerability to ongoing anthropogenic global change (Pallares et al., in press). Dave’s work also shows that the way aquatic insects obtain oxygen underpins their sensitivity to global change, particularly the combined impacts of rising temperatures and anoxia.

Gas exchange mechanisms also seem to be important in setting body size limits in aquatic insects, providing a novel explanation for the seagull-sized dragonflies of the Palaeozoic. In addition, the Bilton group seeks to understanding how freshwater insects succeed in invading saline waters (Pallares et al., 2017), a topic being investigated in our most research grant. Recently, we have also shown that the same physiological rules appear to govern the evolution of diving in all animals, from water beetles to great whales (Verberk et al., 2020)

Dr Rich Boden is an expert on the physiology and biochemistry of sulfur-oxidising Bacteria. These are split into 1) chemolithoautotrophs – those that use CO2 by capturing electrons from chemical oxidation reactions and using them for respiration; 2) chemolithoheterotrophs – those that grow on organocarbon compounds such as sugars etc but also capture electrons from chemical oxidation reactions to supplement respiration (allowing them to attain higher growth yields). His group’s work has recently focussed on physiological capabilities in marine Bacteria from deep-sea hydrothermal vents versus shallow-sea cold vents, both of which emit hydrogen sulfide and CO2, but at different temperatures, pressures and ionic strengths. Using geochemical modelling to predict the relative amounts of carbon available to organisms at each site, they have mapped this onto the biochemical and genome-predicted functionality of known organisms, facilitating a better understanding of organism-environment interactions in hard to sample regions.

Selected publications

Trees

Fauset S, Freitas HC, Galbraith DR, et al (2018) Differences in leaf thermoregulation and water use strategies between three co-occurring Atlantic forest tree species. Plant Cell & Environment 41: 1618–1631.

Fauset S, Oliveira L, Buckeridge MS, et al (2019) Contrasting responses of stomatal conductance and photosynthetic capacity to warming and elevated CO2 in the tropical tree species Alchornea glandulosa under heatwave conditions. Environmental & Experimental Botany 158: 28-39.

Hubau W, …(Incl Fauset S) et al (2020) Asynchronous carbon sink saturation in African and Amazonian tropical forests. Nature 579: 80-87.

Sullivan MJP, …(Incl Fauset S) et al (2020) Long-term thermal sensitivity of Earth’s tropical forests. Science 368: 869-874

Insects

Pallarés S, …(Incl Bilton DT) et al (2017) The chicken or the egg? Adaptation to desiccation and salinity tolerance in a lineage of water beetles. Molecular Ecology 26: 5614–5628.

Pallarés S, ….(inc. Bilton DT) et al. (2021) Loss of heat acclimation capacity could leave subterranean specialists highly sensitive to climate change. Animal Conservation

Verberk WCEP,…. Bilton DT (2018) Does plasticity in thermal tolerance trade off with inherent tolerance? The influence of setal tracheal gills on thermal tolerance and its plasticity in a group of European diving beetles. Journal of Insect Physiology 106: 163-171.

Verberk WCEP, …., Bilton DT (2020) Universal metabolic constraints shape the evolutionary ecology of diving in animals. Proceedings of the Royal Society B 287: 20200488

Bacteria

Hutt LP, … Boden R (2020) Insights into growth kinetics and roles of enzymes of Krebs’ cycle and sulfur oxidation during exochemolithoheterotrophic growth of Achromobacter aegrifaciens NCCB 38021 on succinate with thiosulfate as the auxiliary electron donor. Archives of Microbiology doi: 10.1007/s00203-020-02028-1.

Scott KM …(inc. Boden R) et al. (2019) Diversity in CO2-concentrating mechanisms among chemolithoautotrophs from the genera Hydrogenovibrio, Thiomicrorhabdus and Thiomicrospira, ubiquitous in sulfidic habitats worldwide. Applied and Environmental Microbiology 85: e02096-18 [Editor’s Choice Article]

Scott KM…(inc. Boden R) et al. (2019) Genomes of ubiquitous marine and hypersaline Hydrogenovibrio, Thiomicrorhabdus and Thiomicrospira spp. encode a diversity of mechanisms to sustain chemolithoautotrophy in heterogeneous environments. Environmental Microbiology. 20: 2686-2708.

Boden R, Hutt LP (2019) Thermithiobacillus Kelly and Wood 2000, 515VP. In: Bergey’s Manual of systematics of Archaea and Bacteria.

Funding

Dr Sophie Fauset (PI with Shalom Addo-Danso - Forestry Research Institute of Ghana). Building capacity to monitor and understand forest response to climate change in Ghana. Global Challenges Research Fund, £47,000.

Dr Sophie Fauset (PI) with international collaborators. Network for Monitoring Canopy Temperature of Forests – netCTF. NERC Global Partnerships Seedcorn Fund £100,000.

Professor Dave Bilton (PI) The evolution of salinity tolerance in aquatic Coleoptera. Fundación Seneca Fellowship for Susana Pallares. €96,000. July 2019-June 2021.