An airlift sampler, a kind of "water hoover", can be used to take samples in the middle of the river from a research vessel. © Norbert Kamjunke/UFZ
The macrozoobenthos, i.e. the aquatic invertebrates visible to the naked eye at the bottom of the water, were in some cases even more severely affected by the environmental disaster in the summer of 2022 than the fish. The gill-breathing mussels and aquatic snails in particular were felled by the toxic mass bloom of the algae Prymnesium parvum caused by high salt concentrations, although other animal groups may also have been affected.
Subproject 10 "Macrozoobenthos" is therefore documenting the damage and recovery of the macrozoobenthos, in particular the mussel population. To this end, all small habitats in the Oder are being investigated, from the groyne fields to the groyne heads to the centre of the river. The wadeable bank zones are sampled several times a year at 12 sampling sites by the Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB). The Helmholtz Centre for Environmental Research (UFZ) investigates the deeper areas of the Border and Western Oder at eight sampling sites from a research vessel. To transport the macrozoobenthos up from the sediment in the middle of the river, an airlift sampler is used, which works in a similar way to a hoover.
The results of the sub-project not only provide insights into the development of the individual animal groups, but also into their species diversity, habitat preferences, filtration capacity in relation to planktonic algae and refugial areas.
