Elevated CO 2 stimulates marsh elevation gain, counterbalancing sea-level rise

• DOI: 10.1073/pnas.0807695106
• Publication Date: 2009-03-27T01:29:49Z
• Authors: J. Adam Langley; Karen L. McKee; Donald R. Cahoon; Julia A. Cherry; J. Patrick Megonigal
• Keywords: Brackish marsh; Salt marsh; Elevation (ballistics)

Tidal wetlands experiencing increased rates of sea-level rise (SLR) must increase soil elevation gain to avoid permanent conversion open water. The maximal rate SLR that these ecosystems can tolerate depends partly on mineral sediment deposition, but the accumulation organic matter is equally important for many wetlands. Plant productivity drives dynamics and sensitive global change factors, such as rising atmospheric CO(2) concentration. It remains unknown how will influence mechanisms determine future tidal wetland viability. Here, we present experimental evidence plant response elevated [CO(2)] stimulates biogenic in a brackish marsh. Elevated (ambient + 340 ppm) accelerated by 3.9 mm yr(-1) this 2-year field study, an effect mediated stimulation below-ground productivity. Further, companion greenhouse experiment revealed was enhanced under salinity flooding conditions likely accompany SLR. Our results indicate stimulating contributions marsh elevation, increases gas, CO(2), may paradoxically aid some coastal counterbalancing seas.