Doctoral Programme on Marine Ecosystem Health and Conservation
 The MARES Researchers and their Research
The effects of anthropogenic stressors on the food quality in estuarine systems
PhD Code: MARES_12_08:
  • Host institute 1: P13 - University of Aveiro
  • Host institute 2: P1 - Ghent University
  • Host institute 3: Professor Dr. João Carlos Marques (Full professor) IMAR-Marine and Environmental Research Centre (IMAR CMA)
Research fields:
  • T1 - Future Oceans: temperature changes - hypoxia - acidifation
  • T2 - Understanding biodiversity effects on the functioning of marine ecosystems
  • Gonçalves Fernando
  • De Troch Marleen
  • Ana Marta Gonçalves (
Contact Person and email: Gonçalves Ana Marta -

Subject description
In the last decades contaminants’ discharges are one of the themes that concerned the scientific community and received special attention by media because of the threat and adverse effects that may cause in aquatic ecosystems (McKnight et al., 2012). The pollutants that cause most damage to the ecosystem are originate from industry and mining including toxic substances such as metals and organic pollutants. Little is known about how natural ecosystems respond to chronic exposure to these contaminants, many of which, especially metals, are non-degradable and therefore accumulate in nature. Anthropogenic pressures often decrease the health and stability of ecosystems, although the precise effects of these stressors on the biochemical components remain largely unknown (Gonçalves et al., 2012; Holliday et al., 2009). Despite the extensive literature on anthropogenic pressures, a more functional approach to trace changes in food webs due to modified biochemical composition of species is lacking so far.
Nutrients, mainly lipids and proteins, are involved in many vital functions of aquatic individuals (Arts et al., 2001; Hibbeln et al., 2006; SanGiovanni and Chew 2005; Teilum et al., 2011).  Since some of them can only be obtained from food and therefore referred to as ‘essential nutrients’ they proved to be useful trophic markers (De Troch et al., in press) and are essential for physiological functions, the overall metabolism of organisms and their prevention of diseases (Balasubramanian et al., 1980; Dalsgaard et al., 2003). Integrating multiple specific biomarkers to assess biochemical responses of estuarine species provides a powerful tool to quantify the health status of an individual in response to anthropogenic stressors and food sources (Masclaux et al., 2012).
This PhD research aims to address the influence of human-induced environmental changes on structural and functional (i.e. food web interactions) biochemical composition of two main estuarine planktonic groups in a southern European estuary (e.g. Mondego estuary, Portugal) by means of (trophic) biomarkers.
Pollutants (e.g. inorganic fertilizers and pesticides) are widely used on agriculture fields worldwide, with the Mediterranean region presenting a large increase of these compounds in the past 20-40 years (Galhano et al., 2011). The intensive usage of pollutants in agriculture areas near ecological coastal wetlands, led to the implementation of the Pesticide-Monitoring programs to recover aquatic systems, such as in the Mondego estuary (Figueira da Foz, Portugal) (Galhano et al., 2011). Nowadays, and according to the information from agricultural cooperatives of Mondego valley, the herbicide Primextra® Gold TZ is the most used herbicide in corn crops fields, whereas Copper is mainly used in fungicides and in pesticides’ constitution. Phytoplankton and zooplankton are widely used in the determination of environmental impacts due to their key position in the food chain. Two main representatives of both trophic levels (e.g. the diatom Thalassiosira weissflogii and the copepod Acartia tonsa) will be used to constitute a simple trophic food chain in lab conditions. This will allow to conduct controlled lab experiments in order to determine and quantify the individual and combined effects of anthropogenic stressors. Stressors will include the herbicide Primextra® Gold TZ and copper as metal pollution. Trophic biomarkers as fatty acid (FA) profiles, proteins’ composition and enzymatic activity will be used to test for potential effects of these stressors on the energy flow between both taxonomic levels. Further modelling of the obtained data will allow to better understand possible community-based responses to a combination of stressors. The outcome of this modelling will be verified with data on abundance, diversity and structure of aquatic communities and also food web interactions and their potential changes in the field as obtained during the parallel postdoctoral research of Dr. Gonçalves.
The specific aims of the proposed PhD research are:
- To assess individual effects of toxicants (e.g. Copper and Primextra® Gold TZ) on biochemical composition (e.g. enzymatic activity, proteins and fatty acid composition) of species from different trophic levels (primary producer and primary consumer);
- To assess multiple-stressor scenarios (e.g. bifactorial combinations) effects on biochemical composition of species at different trophic levels;
- To develop an ecotoxicological model of the effects of environmental contaminants on food webs and, thus, on food quality, using experimental data for calibration and validation.
This PhD research is imbedded in the ecotoxicology research that is conducted at the University of Aveiro, in collaboration with IMAR-CMA UC. Furthermore it is supported by the trophic ecology research at the UGent research group Marine Biology. The interaction between these research fields implies an important added value as it guarantees a more integrated approach to impact studies. Integrated knowledge is essential to evaluate the health of marine ecosystems and to take correct conservation measurements were needed.
Within this consortium, it is very feasible that this PhD topic yields a PhD thesis after 3 years as there is a perfect balance between short-term lab experiments, biochemical lab analyses and valorisation of the findings through modelling and comparison with available field data. In addition, there is a certain flexibility in the timing of the experiments according to the timeframe and the interests of the student.
  • Arts, M.T., Ackman, R.G. and Holub, B.J. (2001). Can J Fish Aquat Sci 58, 122 – 137.
  • Balasubramanian, R., Seetharamulu, P. and Raghunathan, G. (1980). Origins of Life 10, 15-30.
  • Dalsgaard, J., St. John, M., Kattner, G., Müller-Navarra, D. and Hagen, W. (2003). Adv Mar Biol 46, 225–340.
  • De Troch, M., Boeckx, P., Cnudde, C., Van Gansbeke, D., Vanreusel, A., Vincx, M. and Caramujo, M.J. (in press). Mar Ecol-Prog Ser. DOI 10.3354/meps09920.
  • Galhano, V., Laranjo, J.G. and Peixoto, F. (2011). Aquat Toxicol 101, 367-376.
  • Gonçalves, A.M.M., Azeiteiro, U.M., Pardal, M.A., De Troch, M. (2012). Estuar Coast Shelf S 109, 70-80.
  • Hibbeln, J.R., Ferguson, T.A. and Blasbalg, T.L. (2006). Int Rev Psychiatr 18, 107–118.
  • Holliday, D.K., Elskus, A.A. and Roosenburg, W.M. (2009). Environ Toxicol Chem 28, 338-345.
  • Masclaux, H., Bec, A., Kainz, M.J., Perrière, F., Desvilettes, C. and Bourdier, G. (2012). Freshwater Biol 57, 696-703.
  • McKnight, U.S., Rasmussen, J.J., Kronvang, B., Bjerg, P.L. and Binning, P.J. (2012).  Sci Total Environ 427-428, 319-331.
  • SanGiovanni, J.P. and Chew, E.Y. (2005). Prog Retin Eye Res 24, 87–138.
  • Teilum, K., Olsen, J.G. and Kragehund, B.B. (2011). Biochim Biophys Acta 1814, 969 – 976.
Employment Details
Employment contract of the University of Aveiro.

Expected outcomes
Results achieved within this PhD research will be presented and discussed at 2-3 scientific meetings, and published in 3-4 peer-reviewed international journals (SCI indexed).
This PhD research will contribute to the development of an ecotoxicological model to predict the influence of anthropogenic activities on trophic food webs, and thus on food quality, and to achieve the level of contamination of estuarine / marine ecosystems according to changes on biochemical composition.
Diffusion of results and addressed methods will be directed to graduation and post-graduation students in short seminars in the proponent and participant institutions. Diffusion of the study rationale and research results will be also directed to the under-graduation educational community (e.g. secondary school students and teachers) during the “Open Day of the University” and the national “Week of Science and Technology” at the University of Aveiro. Moreover, we will put additional effort into the preparation and publication of a manuscript in the journal CAPTAR. This is a periodic journal, held by the University of Aveiro, that aims to diffuse studies and new achievements made by scientists at the Univ. of Aveiro in the field of life sciences and environment, which is focused at students and teachers of the basic and secondary scholar levels. Diffusion to broader publics will be envisaged by posting updated information about the PhD research via Department of Biology/University of Aveiro (, IMAR-CMA ( and websites.

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