Payne Andrew R, Burdick David M, Moore Gregg E, Wigand Cathleen
Jackson Estuarine Laboratory, School of Marine Sciences and Ocean Engineering, University of New Hampshire, Durham, NH 03824, U.S.A.
Office of Research and Development-Center for Environmental Measurement and Modeling United States Environmental Protection Agency, Narragansett, RI 02882, U.S.A.
J Coast Res. 2021 Jul 1;37(4):771-778. doi: 10.2112/jcoastres-d-20-00072.1.
Salt marshes can build in elevation with sea-level rise through accumulation of inorganic sediment and organic matter, but marshes worldwide are under threat of drowning due to rapid rates of sea-level rise that outpace natural marsh building rates. The application of a thin layer of sediment to the marsh surface (thin-layer placement [TLP]) is a tool to build elevation and decrease flooding stress, but its effects on marsh plants are understudied, especially in New England. In a novel application of a marsh organ experiment (i.e. rows of pots at different elevations), the addition of 10 cm of sand to pots planted with Spartina alterniflora and Spartina patens resulted in fewer stems than controls for S. patens but not S. alterniflora after 2 months. However, total biomass and root mass were not significantly impacted for either species, suggesting plants will fully recover from TLP over longer timescales. Effects of TLP on biomass and stem density did not vary significantly by elevation. Although long-term research is still needed, short-term equivalency in biomass between TLP treatments and controls suggests TLP of 10 cm is a promising strategy to enhance the ability of marshes to build vertically as sea level rises in New England.
盐沼可以通过无机沉积物和有机物质的积累随着海平面上升而升高海拔，但由于海平面上升速度超过了天然盐沼的建造速度，全球范围内的盐沼正面临被淹没的威胁。在盐沼表面施加一层薄薄的沉积物（薄层铺设 [TLP]）是一种提高海拔和减轻洪水压力的方法，但其对盐沼植物的影响研究较少，尤其是在新英格兰地区。在一项新颖的盐沼器官实验应用中（即在不同海拔高度设置成排的花盆），在种植互花米草和光鳞米草的花盆中添加10厘米沙子后，两个月后，光鳞米草的茎比对照组少，但互花米草没有。然而，两种植物的总生物量和根生物量均未受到显著影响，这表明植物在更长的时间尺度上会从薄层铺设中完全恢复。薄层铺设对生物量和茎密度的影响在不同海拔高度上没有显著差异。尽管仍需要长期研究，但薄层铺设处理和对照组之间生物量的短期等效性表明，10厘米的薄层铺设是一种有前景的策略，可以增强新英格兰地区盐沼在海平面上升时垂直建造的能力。
