Ramsy Agha, PhD
Research Topics
Effects of parasites on food webs
Parasites are rarely included in our understanding of food webs. Yet, evidence shows that parasites largely modulate trophic interactions: They can, for example, make their hosts more susceptible to predation and they serve themselves as food for other organisms. To disentangle and characterize these potential effects at the base of pelagic food webs, we explore the interface between phytoplankton, zooplankton and their pathogens using laboratory experiments under controlled conditions.
Effects of parasites on food webs
Ecological significance of the chemical diversity in cyanobacteria
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Cyanobacteria produce an enormously diverse array of secondary metabolites, some of which are potent toxins. However, single strains produce different sets of these compounds. We classify subpopulations based on their chemical properties and study their ecological features separately, with the aim of elucidating the biological role of these compounds.
Ecological significance of the chemical diversity in cyanobacteria
Host - Parasite
Co-evolution
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Parasites and their hosts are caught in an endless struggle of reciprocal adaptations. This reciprocal selection is among the most pervasive selective forces in nature, responsible for the genesis and maintenance of genetic diversity. Using laboratory isolates of phytoplankton and their chytrid parasites, we perform experimental evolution assays for test fundamental evolutionary hypotheses. Since these organisms have very short generation times, they allow us to observe evolution in real time!
Host - Parasite
Co-evolution
Harmful algal blooms
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The massive proliferation of algae is a threat from an ecological as well as a public health perspective. We produce ecological knowledge on the biology of harmful algae and use it to help to develop applied tools to mitigate the risks associated to these phenomena, such as innovative monitoring strategies.
Harmful algal blooms
Disease dynamics in a changing world
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Climate change, increasing eutrophication, emerging pollutants like micro- and nanoplastics. Whereas it has become clear that these threats are afecting ecosystems worldwide, this knowledge is rarely studied in the context of wildlife disease. Will the world in the Anthropozene become a "sicker" world? Using different organismal systems, we test for effects of emerging stressors on the incidence of diseases in natural ecosystems.
Disease dynamics in a changing world