Stock Photo - 05 June 2023, Brandenburg, Criewen: Steffi Lemke (Greens), Federal Minister for the Environment, Till Backhaus (l., SPD), Minister for the Environment of Mecklenburg-Western Pomerania, Axel Vogel (2nd from right, Greens), Minister for the Environment of Brandenburg and Dirk Treichel (r), Head of the Lower Oder Valley National Park, stand at the German-Polish border river Oder and take a photo of themselves after measuring the electrical conductivity of the water to determine the salinity in the river. Prior to the Oder Conference, Federal Environment Minister Steffi Lemke met with Brandenburg's Environment Minister Axel Vogel (both Greens) and Mecklenburg-Western Pomerania's Environment Minister Till Backhaus (SPD) on Monday evening in Criewen on the border river. At the Oder conference on the following day, the protection of the Oder ecosystem will be discussed. According to the Ministry of the Environment, this will involve the effects of the climate crisis and pollution on the river. Last summer, there was a mass fish kill in the Oder River. Experts in Germany and Poland concluded that most likely the toxic effect of the algae bloom had caused the death of the fish. Photo: Patrick Pleul/dpa. - Criewen/Brandenburg/Germany