Building the future by doing more together

CLIMAFUN-CLImate Changes and Potencial Impact on Soil FUNctional Ecology
Coordinator - Susana Loureiro
Programme - PTDC/AAC-CLI/104960/2008
Execution dates - 2010-04-01 - 2013-09-30 (42 Months)
Funding Entity - Fundação para a Ciência e a Tecnologia
Funding for CESAM - 188352 €
Total Funding - 188352 €
Proponent Institution - Universidade de Aveiro


One of the most prioritised research areas nowadays is climate change because extreme environmental conditions can become rapidly natural stressors and impair ecological receptors. For example, studies of the effects of UV radiation as a natural stressor are innumerous and in the last decades have grown following awareness about ozone depletion. Pollution, climate and global change are challenging the sustainability of terrestrial ecosystems. Mixture toxicity, multiple stressors and interactions with natural stressors are one of the areas where Risk Assessment (RA) must be considerably improved. As well as exposure to combinations of toxic chemicals, non-chemical stressors can interact either directly with chemicals through changing bioavailability or indirectly through changing organism biology. While there is some information on the mechanisms behind the interactions within chemical mixtures, little is known about how chemical and non-chemical stressors may interact. For example, non-chemical stressors may cause significant changes in the physiology of organisms that may or may not reveal themselves as effects at the individual level, depending on the plasticity of the species regulatory mechanisms. Furthermore, effects at the one individual level (species) may or may not modify the food web dynamics, hence the way ecosystems function. The role of na increased exposure to UV radiation due to the ozone depletion, increase of temperature or severe drought and the way they influences the ecotoxicity of chemicals and the way species react, is still very much unclear.

The challenge to be tackled here is to assess multifunctional stressors, using bioassays with soil organisms and plants, where interaction could occur synergistically or antagonistically for different dose levels and dose ratios. This will be done by combining exposure to natural stressors with chemical substances, in terrestrial model organisms that play crucial roles in nutrient cycling in soil. The edaphic organisms are the isopod Porcellionides pruinosus, the collembolan Folsomia candida, one of the mostly used in soil
ecotoxicology and the plants are the dicotyledonous rapid cycle Brassica rapa, the monocotyledonous Avena sativa and the water cress Nasturtium officinale, the latter used mainly for human consumption.

The main questions addressed in this project are:
1) Do chemicals combined with natural stressors behave like chemical mixtures?
2) What is the influence of an increased natural stressor on the chemical effect in organisms?
3) Can the models for mixture effects "Concentration Addition" and "Independent "action" be applied in this kind of combined stressors, or there are some deviations to the models? Are those effects of ecological significance?
4) Is it possible to provide a mechanistic/biochemical foundation of the potential phenotype alterations?

Answering these questions will raise novel approaches to:
1) assess scenarios with probable contamination from agricultural sources in different climatic areas,
2) preventing additional soil toxicity caused by climate changes and also
3) improving soil quality and human health.

Several pesticides (e.g. imidacloprid, diflubenzuron, prochloraz) and metal elements (e.g. cadmium, copper, lead) and natural stressors (e.g. extreme temperatures, flood or drought conditions, UV radiation) will be chosen and tested using bioassays (objective 1 and 2). The selection of toxicity tests should be consistent with ERA practices and therefore relevant taxonomic species selected. The final results will be fit into the models described above and the combined effects studied and discussed (objectives 1, 2 and 3). Different parameters used in the same experiments will be also studied to investigate if different endpoints can re-direct to diferente behaviors for the same chemical combination. We expect that this study will bring us more information on organisms' sensitivity to several combinations of chemical and natural stressors and on the mechanistic response they provide.




Members on this project

technician

grant holder
Jacinta M M Oliveira
grant holder
Maria Pavlaki
grant holder
Marta S. Monteiro
researcher

CESAM Funding: