Marsh accretion and sediment accumulation in a managed tidal wetland complex of Delaware Bay
Marsh accretion and sediment accumulation in a managed tidal wetland complex of Delaware Bay
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DOI：
10.1016/j.ecoleng.2016.03.045
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发表时间：
2016-07-01
影响因子：
3.8
通讯作者：
Sommerfield, Christopher K.
中科院分区：
文献类型：
--
作者：
Boyd, Brandon M.;Sommerfield, Christopher K.
创建湿地蓄水池是为了提供生态效益，如改善水质、控制蚊子和候鸟栖息地。Prime Hook国家野生动物保护区位于特拉华湾西南海岸，由四个相互关联的湿地管理单元组成。从特拉华湾到机组I和IV的潮汐流入是自然发生的，而流向机组II和机组III的潮流自20世纪80年代中期以来一直受到潮汐闸门的限制。为了评估保护区沼泽的增长状况，并为正在进行的恢复提供信息，我们调查了土壤物理性质，并对12个地点采集的岩芯进行了Cs-137和Pb-210放射性年代学研究。结果表明，沼泽的增长是由矿物沉积和有机质积累共同驱动的，两者的相对比例在湿地单元之间和湿地单元内是不同的。吸积速率(0.11-0.54 cm/年)与有机质积累显著相关，与矿物沉积物积累无关。这些关系表明，在沼泽恢复战略中，除了矿物沉积物的供应外，还必须考虑生物对沼泽增长的贡献，例如地下生物量生产力。自20世纪初以来，在其中8个地点，矿物沉积物对土壤总体积的贡献在蓄水工程之前已显著减少，可能与自然过程关闭两个潮汐入海口有关。相比之下，有机土壤体积在同一时间跨度内的变化相对较小。在七个地点，沼泽正在以略低于当地相对海平面上升速度(0.34+/-0.03厘米/年)的速度增长，从长远来看，可能会淹没。需要在保护区进行更多的研究，以更好地调整沼泽淤积、验潮仪的相对海平面和湿地海拔变化的测量结果。(C)2016爱思唯尔B.V.保留所有权利。
Wetland impoundments are created to provide ecological benefits such as water quality improvement, mosquito control, and migratory bird habitat. Prime Hook National Wildlife Refuge, located on the southwestern shore of the Delaware Bay, is composed of four interconnected wetland management units. Tidal inflow from Delaware Bay to Units I and IV occurs naturally, whereas flow to Units II and III has been restricted by tidal gates since the mid-1980s. To assess the accretionary status of Refuge marshes and inform an ongoing restoration, we investigated soil physical properties and developed Cs-137 and Pb-210 radiochronologies for cores collected at twelve sites. Results indicate that marsh accretion is driven by a combination of mineral sediment and organic matter accumulation, the relative proportions of which vary among and within the wetland units. Accretion rates (0.11-0.54 cm/y) were found to be significantly correlated with organic matter accumulation but not with mineral sediment accumulation. These relationships demonstrate that biotic contributions to marsh accretion, such as belowground biomass productivity, must be considered in marsh restoration strategies, in addition to the supply of mineral sediment. At eight of the sites, the contribution of mineral sediment to the total volume of the soils has decreased significantly since the early 1900s, predating the impoundment works, perhaps in association with closure of two tidal inlets by natural processes. By comparison, changes in organic soil volume were relatively small over the same time span. At seven of the sites the marsh is accreting at, to just below, the rate of local relative sea-level rise (0.34 +/- 0.03 cm/y) with potential for submergence on the long term. Additional research at the Refuge is needed to better align measurements of marsh accretion, relative sea-level from tide gauges, and wetland elevation change. (C) 2016 Elsevier B.V. All rights reserved.