Tidal freshwater forest accretion does not keep pace with sea level rise
Tidal freshwater forest accretion does not keep pace with sea level rise
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DOI：
10.1111/gcb.12009
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发表时间：
2012-12-01
影响因子：
11.6
通讯作者：
Craft, Christopher B.
中科院分区：
文献类型：
--
作者：
Craft, Christopher B.
在南大西洋（美国佐治亚州）海岸的奥吉奇河、阿尔塔马哈河和萨提拉河的潮汐淡水森林（潮汐森林）中测量了土壤特性、积聚和积累，以表征这些未经充分研究的、不常见的生态敏感湿地的碳 (C) 固存和养分（氮-N、磷-P）积累。还在经历盐水入侵的潮汐森林（南纽波特河）中测量了碳固存以及氮和磷积累，以评估海平面上升 (SLR) 和盐水入侵对碳、氮和磷积累的影响。最后，将潮汐森林的土壤积聚和积累与下游潮汐新鲜、咸水和盐沼植被进行比较，以衡量潮汐森林对 SLR 的反应。使用C-137和Pb-210测定的土壤积聚平均分别为1.3和2.2毫米年(-1)，并且远低于最近乔治亚州海岸SLR的速率（3.0毫米年(-1)）。健康的潮汐森林土壤封存碳（4982 g m(-2) yr(-1)）、累积氮（3.25.3 g m(-2) yr(-1)）和磷（0.290.56 g m(-2) yr(-1)）以及截留的矿物沉积物（340650 g m(-2) yr(-1)）。健康的潮汐森林和经历盐水入侵的南纽波特河潮汐森林在长期吸积、碳固存和养分积累方面没有差异。加速的SLR可能会导致潮汐森林的减少以及寡盐沼泽和咸水沼泽的扩张，这些沼泽的土壤增生超过了目前SLR的速度。将潮汐森林转变为沼泽将导致某些生态系统服务的增加，例如碳封存和沉积物捕获，但会牺牲其他服务（例如反硝化、迁徙鸣禽栖息地）。随着全球变暖导致海平面上升，潮汐森林及其提供的生态系统服务面临着脆弱的未来，除非它们能够向上游迁移，而由于地形限制和沿海地区日益城市化，这在大多数地区是不可能的。
Soil properties, accretion, and accumulation were measured in tidal freshwater forests (tidal forests) of the Ogeechee, Altamaha, and Satilla rivers of the South Atlantic (Georgia USA) coast to characterize carbon (C) sequestration and nutrient (nitrogen-N, phosphorus-P) accumulation in these understudied, uncommon, and ecologically sensitive wetlands. Carbon sequestration and N and P accumulation also were measured in a tidal forest (South Newport River) that experiences saltwater intrusion to evaluate the effects of sea level rise (SLR) and saltwater intrusion on C, N and P accumulation. Finally, soil accretion and accumulation of tidal forests were compared with tidal fresh, brackish and salt marsh vegetation downstream to gauge how tidal forests may respond to SLR. Soil accretion determined using C-137 and Pb-210 averaged 1.3 and 2.2 mm yr(-1), respectively, and was substantially lower than the recent rate of SLR along the Georgia coast (3.0 mm yr(-1)). Healthy tidal forest soils sequestered C (4982 g m(-2) yr(-1)), accumulated N (3.25.3 g m(-2) yr(-1)) and P (0.290.56 g m(-2) yr(-1)) and trapped mineral sediment (340650 g m(-2) yr(-1)). There was no difference in long-term accretion, C sequestration, and nutrient accumulation between healthy tidal forests and tidal forests of the South Newport River that experience saltwater intrusion. Accelerated SLR is likely to lead to decline of tidal forests and expansion of oligohaline and brackish marshes where soil accretion exceeds the current rate of SLR. Conversion of tidal forest to marshes will lead to an increase in the delivery of some ecosystem services such as C sequestration and sediment trapping, but at the expense of other services (e.g. denitrification, migratory songbird habitat). As sea level rises in response to global warming, tidal forests and their delivery of ecosystem services face a tenuous future unless they can migrate upriver, and that is unlikely in most areas because of topographic constraints and increasing urbanization of the coastal zone.