Are geochemical regime shifts identifiable in river waters? Exploring the compositional dynamics of the Tiber River (Italy).

摘要: Abstract Rivers are dynamic and sensitive systems that change their chemical composition from source to mouth. This is due the influence of a set variables controlled by hydro-litho-eco-atmospheric processes anthropic pressures which are, in turn, affected catchment attributes. work proposes new way thinking about river geochemistry focused on environmental interconnections rather than single variables. Abrupt changes system state (composition) certain media, driven perturbations, may trigger Geochemical Regime Shifts (GRSs). eventuality explored Tiber River (central Italy) chemistry Compositional Data Analysis, robust Principal Component Analysis score-distance graphs. variability interlinks between response forcing investigated for different drained areas. A potential GRS detected major elements lower reaches resulting threshold-like caused lithological forcing. On contrary, trace respond gradually drivers, showing no abrupt changes. The findings outline mechanisms factors influencing river's self-restoring capability at basin-wide scale, providing better comprehension circumstances controlling equilibrium dynamics water systems.