READ ALSO: One in three people in Germany report heat-related health problemsWhat do the low water levels mean for people in Germany? In Serbia, for example, falling water levels have exposed wrecked Nazi warships in the Danube, creating new hazards for navigation. Because of the low water levels, cargo ships are currently operating with significantly reduced loads. Low water combined with rising temperatures can also reduce oxygen levels, putting additional stress on aquatic ecosystems. According to reports in Der Spiegel, the government has issued invitations for an expert conference on the historically low water levels, scheduled to take place on Thursday in Bonn.