SHYFEM/EUTRO A Simple nutrient dynamics model

Wetlands are considered the most biologically diverse of all ecosystems and important habitats for many species. Plant life found in wetlands includes mangrove, water lilies, cattails, sedges, tamarack, black spruce, cypress, gum and many others. Animal life includes many different amphibians, reptiles and birds. In many locations, such as the United Kingdom, Norway, South Africa and the United States, wetlands are the subject of conservation efforts and Biodiversity Action Plans. Wetlands are the transitional zones between terrestrial and aquatic ecosystems. They are dynamic from the hydrological and ecological points of view. Land-based nutrients reach wetlands before reaching other aquatic ecosystems such as lakes or the marine environment. In healthy wetlands nutrients are taken up by primary producers and processed further through the upper levels of the food web supporting all the organisms living there, so that wetlands work as "kidneys" that prevent the over fertilization of aquatic ecosystems. However, wetland ecosystems do not have an unlimited assimilation capacity for nutrients and excess nutrients cause problems that may result in the loss of biodiversity and inhibition or total loss of the ecological functions. To analyze problems in wetlands caused by excess nutrients, biogeochemical models can be useful tools. There are many reasons for using numerical models.