Variation in nutrient availability for aquatic phototrophs and its ecological consequences

Chapter 17. Nutrients, frequently phosphorus and/or nitrogen, often limit aquatic primary productivity. The availability of nutrients required by phototrophs varies with chemical and biological species, site and season. A rapidly increasing, resource-demanding human population that uses water as a convenient waste-disposable system has caused widespread nutrient pollution leading to ‘eutrophication’. In conjunction with other multiple pressures such as climate change, this has altered the natural communities in an ecosystem, and caused biodiversity loss. It also causes a cascade of undesirable consequences for human use of water, including the growth of potentially toxic microalgal and macroalgal blooms, and deoxygenation leading to fish kills and the release of nutrients from the sediment to the water. Remediation, driven by legislation, is focused on limiting nutrient losses from agricultural systems while maintaining the ability to produce food sustainably and increasing nutrient capture in works treating domestic and industrial waste and the production of a circular economy for nutrients.