AMEO at UFZ, Leipzig – Barbara Mader (2026)

Every Summer Semester, Ecotox Master students do a 2-month internship or AMEO (Applied Module at an External Organization). Today, Barbara shares her AMEO experience at the Helmholtz Centre for Environmental Research (UFZ) in Leipzig.

Hello, my name is Barbara Mader, and this summer (May – July of 2026) I completed my internship at the Helmholtz Centre for Environmental Research (UFZ) in Leipzig. The UFZ has five ecotoxicology departments, and I joined the System-Ecotoxicology department. The main task of my internship was sampling in the UFZ stream mesocosm, assisting another master student in her research. The mesocosm in Leipzig consists of 47 artificial streams, with each stream measuring 14 m in length, and is used to assess the long-term effects of pesticide contamination and temperature stress on the macroinvertebrate communities.

Sampling the Stream Mesocosm

Our work included taking samples with a net and assessing the stream vegetation cover (Figure 1). This sample was then sieved and poured step by step into trays for us to identify and count the macroinvertebrates (Figures 1 and 3). Working in the mesocosm has taught me much about identifying macroinvertebrates, most of which are insect larvae but also include various worms and snails, as well as about working on this specific kind of fieldwork.

Since the mesocosm is situated right on the grounds of the UFZ in Leipzig, it has all the charms of fieldwork but also all the amenities of working in the lab. A highlight of this internship was a visit from a camera team interviewing our supervisor and filming us in the mesocosm.

Figure 1: First step of the mesocosm work, assessing the vegetation cover in the stream and then taking a net sample and typical sampling tray in the mesocosm, how many macro invertebrates can you spot?
Figure 2: snapshots of the mesocosm in Leipzig at the UFZ and funky never-before-seen macro invertebrate
Figure 3: Trichoptera larva, presumed to be Limnophilus lunatus

From Streams to the Laboratory

Sampling all 47 streams took the two of us one month and half. This was followed by maintenance work in the lab and also in the mesocosm. The working group has been cultivating long-term Daphnia magna cultures adapted to different temperatures and esfenvalerate concentrations for approximately 80 months. These cultures are used in experiments, for example, to measure enzyme activity. We took care of these cultures by changing their culture medium every three days and performing a generation change by the end of every month. If necessary, we also maintained Culex cultures. I finished my internship at the UFZ by prepping the D. magna cultures for a salinity experiment. Overall, the internship had us working quite independently, but there were weekly meetings of all the UFZ ecotoxicology departments to keep each other up to date. I did not live in Leipzig during this time, as I am from a nearby city (Halle) and lived at home, but with a 90 min commute.