Nonlinear responses in salt marsh functioning to increased nitrogen addition
Salt marshes provide storm protection to shorelines, sequester carbon [C], and mitigate coastal eutrophication. These valuable coastal ecosystems are confronted with increasing nitrogen [N] inputs from anthropogenic sources, such as agricultural runoff, wastewater, and atmospheric deposition. To inf...
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| Otros Autores: | , |
| Formato: | Artículo |
| Lenguaje: | Español |
| Materias: | |
| Acceso en línea: | http://ri.agro.uba.ar/files/intranet/articulo/2015vivanco.pdf LINK AL EDITOR |
| Aporte de: | Registro referencial: Solicitar el recurso aquí |
| Sumario: | Salt marshes provide storm protection to shorelines, sequester carbon [C], and mitigate coastal eutrophication. These valuable coastal ecosystems are confronted with increasing nitrogen [N] inputs from anthropogenic sources, such as agricultural runoff, wastewater, and atmospheric deposition. To inform predictions of salt marsh functioning and sustainability in the future, we characterized the response of a variety of plant, microbial, and sediment responses to a seven-level gradient of N addition in three Californian salt marshes after 7 and 14 months of N addition. The marshes showed variable responses to the experimental N gradient that can be grouped as neutral [root biomass, sediment respiration, potential carbon mineralization, and potential net nitrification], linear [increasing methane flux, decreasing potential net N mineralization, and increasing sediment inorganic N], and nonlinear [saturating aboveground plant biomass and leaf N content, and exponentially increasing sediment inorganic and organic N]. The three salt marshes showed quantitative differences in most ecosystem properties and processes rates; however, the form of the response curves to N addition were generally consistent across the three marshes, indicating that the responses observed may be applicable to other marshes in the region. Only for sediment properties [inorganic and organic N pool] did the shape of the response differ significantly between marshes. Overall, the study suggests salt marshes are limited in their ability to sequester C and N with future increases in N, even without further losses in marsh area. |
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| ISSN: | 0012-9658 |