NASA Goddard Institute for Space Studies, New York, NY 10025;
Division of Biology and Paleoenvironment, Lamont-Doherty Earth Observatory, Palisades, NY 10964.
Proc Natl Acad Sci U S A. 2018 Oct 9;115(41):10281-10286. doi: 10.1073/pnas.1715392115. Epub 2018 Sep 24.
New York City (NYC) is representative of many vulnerable coastal urban populations, infrastructures, and economies threatened by global sea level rise. The steady loss of marshes in NYC's Jamaica Bay is typical of many urban estuaries worldwide. Essential to the restoration and preservation of these key wetlands is an understanding of their sedimentation. Here we present a reconstruction of the history of mineral and organic sediment fluxes in Jamaica Bay marshes over three centuries, using a combination of density measurements and a detailed accretion model. Accretion rate is calculated using historical land use and pollution markers, through a wide variety of sediment core analyses including geochemical, isotopic, and paleobotanical analyses. We find that, since 1800 CE, urban development dramatically reduced the input of marsh-stabilizing mineral sediment. However, as mineral flux decreased, organic matter flux increased. While this organic accumulation increase allowed vertical accumulation to outpace sea level, reduced mineral content causes structural weakness and edge failure. Marsh integrity now requires mineral sediment addition to both marshes and subsurface channels and borrow pits, a solution applicable to drowning estuaries worldwide. Integration of marsh mineral/organic accretion history with modeling provides parameters for marsh preservation at specific locales with sea level rise.
纽约市（NYC）是许多受海平面上升威胁的沿海城市人口、基础设施和经济的代表。纽约市牙买加湾的沼泽地不断流失，这是世界上许多城市河口的典型特征。这些关键湿地的恢复和保护的关键是了解它们的沉积作用。在这里，我们使用密度测量和详细的堆积模型，重建了牙买加湾沼泽地三个世纪以来的矿物和有机沉积物通量的历史。通过对各种沉积物芯分析，包括地球化学、同位素和古植物学分析，利用历史土地利用和污染标志物来计算堆积速率。我们发现，自公元 1800 年以来，城市发展极大地减少了稳定沼泽的矿物沉积物的输入。然而，随着矿物通量的减少，有机物质通量增加。虽然这种有机积累的增加使得垂直积累超过了海平面上升的速度，但减少的矿物含量导致了结构脆弱和边缘失效。现在，沼泽地的完整性需要向沼泽地和地下渠道以及借土坑中添加矿物沉积物，这是一种适用于全球溺水河口的解决方案。将沼泽地矿物/有机堆积历史与模型相结合，为特定地点在海平面上升时的沼泽地保护提供了参数。
