In natural tidal marshes, nutrient fertilization stimulates complex responses, bringing into question the suitability of nutrient-rich dredged material as a substrate for tidal marsh restoration. We examined vegetation and elevation trends in the constructed tidal marshes at Poplar Island, Maryland where fine-grained dredged material (high nutrient) and locally dredged sand (low nutrient) were used as substrates. Macrophyte production was higher and root:shoot ratios lower in dredged material marshes. Measured vertical accretion was similar in dredged material (7.4 ± 0.6 mm y⁻¹) and sand (6.4 ± 0.9 mm y⁻¹) marshes, and is keeping pace with local sea-level rise. A detailed carbon budget was developed for one dredged material marsh to examine carbon dynamics under high nutrient availability. High annual macrophyte production combined with small exports via tidal exchange and methane emissions resulted in an annual carbon burial of 206 g C m⁻² y⁻¹, and calculated vertical accretion of 6.5 mm y⁻¹ from organic matter. This is attributed to the contribution of organic matter from aboveground biomass due to protection from perimeter dikes constructed to contain dredged material during placement, reducing marsh exposure and organic matter export. With appropriate design and management, fine-grained, high-nutrient dredged material makes a suitable substrate for tidal marsh restoration.

在天然潮汐沼泽中，养分施肥会刺激复杂的反应，从而使富含营养的疏dr材料作为潮汐沼泽恢复基质的适用性受到质疑。我们检查了马里兰州白杨树岛人工潮汐沼泽中的植被和海拔变化趋势，这里以细粒疏material材料（高养分）和局部疏sand沙子（低养分）作为基质。在疏material的物质沼泽中，大型植物的产量较高，根：茎比率较低。在疏material物料（7.4±0.6 mm y ^-1）和沙子（6.4±0.9 mm y ^-1）中测得的垂直吸积相似）沼泽，并与当地海平面上升保持同步。为一个疏dr的物质沼泽制定了详细的碳预算，以检查在高养分利用率下的碳动态。年生植物的高产量加上通过潮汐交换和甲烷排放的少量出口，导致了每年206 g C m ^-2 y ^-1的碳埋葬，并且计算出的垂直吸积为6.5 mm y ^-1来自有机物。这归因于地上生物质对有机物的贡献，这归因于在放置期间免受构造成容纳疏material物质的周边堤防的影响，从而减少了沼泽接触和有机物出口。通过适当的设计和管理，细粒，高养分的疏material材料将成为潮汐沼泽修复的合适基质。