PhD position: Global change impact on plankton ecophysiology
In order to optimize nutrient uptake and light acquisition, different phytoplankton species have opted for different strategies resulting in large interspecific functional trait variability. Functional traits are the morphological, physiological, phenological, and behavioral characteristics of an organism that influence its performance or fitness. Intraspecific variability also exists, and it has for example been shown that different strains of one species can differ in a range of cellular characteristics including cell size and biochemical composition. Despite its potential significance for trophic interactions and nutrient cycling, trait variability between individual phytoplankton cells has not yet been characterized. Moreover, this information is particularly relevant in the context of global change as it places organisms under enormous pressure by radically changing the environment in which they live, hence directly altering individual traits. This project aims at filling these gaps by determining to which extent variability in phytoplankton traits is affected by global change and by testing how micro- and mesozooplankton respond to phytoplankton trait variability. The results from this project will enable us to evaluate individual producer and consumer adaptations that may dampen the impacts of global change.
Despite the threat posed by global change, we lack predictive knowledge since most studies to date have focused on single stressors. This project will realistically assess the impact of simultaneous changes in temperature, pH, nutrients, and salinity on planktonic organisms and will provide a robust evaluation of how these organisms are and will be affected by abiotic changes. To do so, you will conduct laboratory experiments with phytoplankton and zooplankton in order to investigate to which extent variability in phytoplankton cell size, biochemical composition, and motility is affected by changes in abiotic parameters, test how micro- and mesozooplankton respond to individual prey quality variability (e.g. through selective and compensatory feeding).
While the available technology has so far limited our capacity to study trait variability, recent advances in the development of measurement methods allow new insights in fine scale processes. Hence, motility will be studied using high-speed high-quality video imaging and the biochemical composition of individual phytoplankton cells will be measured using Laser Desorption Ionization Mass Spectrometry (LDI-MS) and Fourier Transform InfraRed (FTIR) microscopy. You will also gain supervising experience by working together with bachelor and master students and will be given the opportunity to present scientific results at international conferences.
For more information about the position and on how to apply please follow the link: https://www.awi.de/nc/en/work-study/jobs/job-offer/detail/jobs/phd-student-in-global-change-impact-on-plankton-ecophysiology.html