Wetlands as Nutrient Sinks

This chapter presents an analysis of the capacity of existing natural wetlands in the Baltic Sea drainage basin to serve as nutrient sinks, in particular, for nitrogen. It presents a geographical information system-based (GIS) wetland distribution map of the whole region, with information about wetland distribution within countries as well as the loss of wetland areas that has occurred in recent decades. The chapter estimates the retention capacity of the atmospheric deposition of nitrogen by the wetlands in the Baltic Sea drainage basin. It also provides results from an 'ecological footprint' analysis of the area of wetlands that the largest cities within the drainage basin appropriate for processing human nitrogen emissions. Wetlands are multifunctional in the sense that they generate several ecosystem services such as supplying habitat for many plants and animals, mitigating floods, recharging aquifers, and improving water quality by removing organic and inorganic nutrients and toxic metals from the water that flows across the wetlands.