Samenvatting

The disruption of nutrient cycles caused by human activities such as agriculture and burning fossil fuels is impacting ecosystem services on global and local scales. The increasing concentration of carbon dioxide in the atmosphere contributes to rising global temperatures and ocean acidification, whereas the accumulation of nutrients in water systems is leading to degradation of water quality and biodiversity. City populations play a major role in carbon dioxide and nutrient emissions as ‘end consumers’ of resources. The current challenge towards more resource-efficient cities is to transform urban metabolism from linear to cyclical. Discharged nutrients and carbon dioxide can be used as input for algae, which fixate carbon very efficiently into energetic storage compounds as starch or lipids. However, cities often lack the space to implement large-scale algae production. This article evaluates the potential of reusing nutrients and carbon dioxide to produce algae, food and biofuel on water nearby coastal and delta cities. First, nutrients and carbon dioxide discharge is estimated and two scenarios are developed. From the cities nutrient production, the potential algal yield is evaluated and translated into feed, food and oil yields. Two delta cities are chosen as case studies: Rotterdam and Metro Manila. The conclusion of this article is that Floating Production can help cities increasing their resilience in the field of food and energy. Floating Production can also contribute to a solution for global land shortage. The combination of food and energy production with floating urban development provides a climate-proof urban expansion in delta and coastal areas.