The 10th International Estuarine Biogeochemistry Symposium-estuaries in a changing world, continues a series of meetings which were first entitled the International Model Estuaries Symposium. The focus of the meeting is Estuarine Biogeochemistry. The meeting has a wide perspective and appeals to marine chemists and biogeochemists as well as scientists working in the boundary zone between chemistry/geochemistry and biology/microbiology. Representing only <1% of the global ocean surface area, estuarine systems have been long recognized as a vitally important connection between the land and the ocean. Estuaries represent an essential pathway for material export from land into ocean. The mixing of freshwater and saline water within an estuarine system results in strong chemical, physical and biological gradients, and there the biogeochemical processes have substantial influence on the water and sediment chemistry. Under the current global change regime, estuaries are particularly vulnerable to both natural and anthropogenic changes, and thus should be examined in a perspective of global change. The objectives of the symposium on “Estuaries in a changing world” are to present recent research results on these dynamic systems including transport and modification of substances across boundaries, natural and anthropogenic processes,balances and box models in relation to short and long-term changes.