Department Aquatic Ecology

The resilience of plankton communities to chemical pollution

Multiple human-induced stressors in the form of chemical pollutants, habitat transformation and climate change are affecting the structure, functioning and adaptive capacity of natural populations and communities. Interaction of multiple stressors occurs over a nested set of adaptive systems that span from cells to food-webs, and resilience is mediated by physiological, ecological and evolutionary responses at different spatial and temporal scales. Our goal is to understand how environmentally relevant exposure scenarios to water-borne micropollutants affect these nested responses within plankton communities, interfere with the processes that maintain biodiversity and functioning of natural systems, impair the ability of communities to adapt to environmental gradients or additional stressors. Key innovative aspects of our approach include the use of environmentally relevant scenarios and exposure levels, the targeting of multiple endpoints at increasing levels of biological complexity, and the use of data acquired at the individual level.

Interactions between Environmental Gradients and Emerging Pollutants in Natural Phytoplankton Communities

Lakes globally contribute to the cycle of nutrients, carbon and green-house gases and are generally among the first ecosystems to encounter novel pollutants of human origin as a consequence of discharge from industrial, urban and agricultural settlements. The final impact of these toxic mixtures on lake ecosystems is not well understood. The analysis of risk and effect require new approaches that consider realistic environmental scenarios, which can potentially help disentangling the effects of a fluctuating environment from the effects of pollutants (multiple stressors). Emerging contaminants such as pharmaceuticals and personal care products pose new concerns for the protection of water, and the assessment of risks associated with water-borne drugs requires realistic exposure levels and a mixture toxicology approach. We want to understand interactions and trade-offs between natural environmental changes and responses to emerging micropollutants in plankton driven systems. In collaboration with Luca Nizzetto (NIVA, Oslo, Norway), we aim at exposing phytoplankton in their natural environment to emerging chemical stressors using novel field methods, for an assessment of the community adaptive capacity.

Pollution-induced evolutionary responses in phytoplankton populations

Natural populations may evolve resistance to pollutants or their mixtures but how these toxic mixtures relate to the evolution of resistance traits and associated fitness costs is not well understood. We interested in the number of generations and the levels of exposure that determine evolutionary adaptation to pollutants, how organisms genetically adapt, and what are the implications of evolved resistance for community dynamics and ecosystem functioning (for example primary production). Questions include: do realistic environmental levels of exposure to micropollutants induce individual responses as phenotypic plasticity? How long phenotypic plasticity is maintained across generations? How long before phenotypic changes are fixed within populations under chemicals' selective pressure? In this project we attempt to experimentally evolve resistant phytoplankton strains (particularly cyanobacteria) by exposing them to water-borne micropollutants in the laboratory. We focus on several aspects that are of key importance to understand the evolutionary ecology of micropollutants exposure.

Metabolism of polar organic xenobiotics in phytoplankton

This project is closely linked to the "Biotransformation in freshwater algae - Identification of transformation products and assessment of environmental relevance" with Juliane Hollender (Uchem).

Identification of transformation products and assessment of environmental relevance