Coastal marshes are globally important, carbon dense ecosystems simultaneously maintained and threatened by sea-level rise. Warming temperatures may increase wetland plant productivity and organic matter accumulation, but temperature-modulated feedbacks between productivity and decomposition make it difficult to assess how wetlands and their thick, organic rich soils will respond to climate warming. Here, we actively increased aboveground plant-surface and below-ground soil temperatures in two marsh plant communities, and found that a moderate amount of warming (1.7°C above ambient temperatures) consistently maximized root growth, marsh elevation gain, and below-ground carbon accumulation. Marsh elevation loss observed at higher temperatures was associated with increased carbon mineralization and increased microtopographic heterogeneity, a potential early warning signal of marsh drowning. Maximized elevation and below-ground carbon accumulation for moderate warming scenarios uniquely suggest linkages between metabolic theory of individuals and landscape-scale ecosystem resilience and function, but our work indicates nonpermanent benefits as global temperatures continue to rise.
|Title||Temperature optimum for marsh resilience and carbon accumulation revealed in a whole ecosystem warming experiment|
|Authors||Alexander J. Smith, Genevieve L. Noyce, J. Patrick Megonigal, Glenn R. Guntenspergen, Matthew L. Kirwan|
|Publication Subtype||Journal Article|
|Series Title||Global Change Biology|
|Record Source||USGS Publications Warehouse|
|USGS Organization||Patuxent Wildlife Research Center; Eastern Ecological Science Center|