Ivana Trbojević researches in the LakeLab | Photo: Martina Bauchrowitz
Ivana Trbojević had already worked on periphyton in her PhD thesis. These algae colonise surfaces under water and can thus also grow on the leaves of underwater plants, the so-called macrophytes. In her project, which she is carrying out together with IGB researcher Sabine Hilt during this year's LakeLab experiment, she is now investigating both the periphyton and the macrophytes. For 4 weeks, cups with macrophytes as well as growth carriers for the periphyton are incubated in five different water depths down to 6 metres in the enclosures of the LakeLab.
Subsequently, the periphyton is scraped off from the growth carriers and the weight of the formed biomass will be measured. In addition, the composition of the periphyton community will be examined via DNA analysis and it will be investigated how much nutrients (phosphorus) the periphyton has absorbed during the four-week incubation period. A nutrient analysis is also carried out for the macrophytes and it will be determined whether the plants have grown during the incubation period. The underlying question is how macrophytes and periphyton react to the changed environmental conditions in the enclosures of the LakeLab: Is their growth inhibited by the brownification of the water with humic substances or is it increased by the skyglow and the resulting increased light at night?
