美国国家航天局（NASA）支持的研究追踪海岸侵蚀的碳成本

美国国家航天局（NASA）支持的研究追踪海岸侵蚀的碳成本

NASA-Supported Study Tracks Carbon Cost of Coastal Erosion

根据一项由NASA支持的最新研究，从得克萨斯州到缅因州，沿海湿地和沼泽每年向海洋释放超过14.5亿磅（660,000公吨）的碳。

From Texas to Maine, coastal wetlands and marshes are releasing more than 1.45 billion pounds (660,000 metric tons) of carbon into the ocean each year, according to new research supported by NASA.

沿海沼泽与森林和苔原一样，在其植物和土壤中储存了大量的碳，但由风暴、海平面（sea level）上升和人类开发引起的变化会影响这些碳的储存和运输方式。

Coastal marshes, like forests and tundra, store large amounts of carbon in their plants and soil, but changes caused by storms, rising seas and human development can affect how that carbon is stored and transported.

这项新研究的作者分析了Landsat影像以及来自美国地质调查局（U.S. Geological Survey）的激光雷达（lidar）高程数据，以追踪1985年至2022年间墨西哥湾沿岸和东海岸的沼泽流失情况。他们估计，尽管侵蚀释放的部分碳被新的沼泽生长所抵消，但每年的净损失仍约为8亿磅（380,000公吨）的碳。

The authors of the new study analyzed Landsat imagery along with lidar elevation data from the U.S. Geological Survey to track marsh loss along the Gulf Coast and Eastern seaboard between 1985 and 2022. They estimate that while some of the carbon released by erosion is offset by new marsh growth, the net loss is still around 800 million pounds (380,000 metric tons) of carbon every year.

侵蚀量因地区和时间段而异。作者发现，在2005年的卡特里娜飓风（Katrina）和2021年的艾达飓风（Ida）之后，密西西比河奎宿五（Delta）地区的海岸侵蚀有所增加，这两场飓风都导致数英里的沿海植被被连根拔起并淹没。作为全国面积最大的沼泽地所在地，该地区输送的沿海碳量超过了整个东海岸。

The amount of erosion varied across regions and time periods. The authors identified increases in coast erosion in the Mississippi River Delta following hurricanes Katrina in 2005 and Ida in 2021, both of which uprooted and submerged miles of coastal vegetation. Home to the nation’s largest marshland by area, the region moved more coastal carbon than the entire Eastern seaboard.

因沼泽侵蚀而位移的大部分碳并没有直接排放到大气中，而是进入了海洋。由于海岸线环境的复杂性，这种空气-陆地-海洋的交换在传统上很难建模，因为海岸线环境在海平面上升、风、潮汐和海洋生物的塑造下不断变化。为了更好地模拟这一过程，NASA戈达德空间研究所（Goddard Institute for Space Studies）正在开发新的模型。更好地理解碳如何沿着我们的海岸线从陆地移动到海洋，可以帮助科学家构建一幅更准确的地球（Earth）碳循环（carbon cycle）全景图。

Most of the carbon displaced by marsh erosion isn’t emitted directly into the atmosphere but enters the ocean. This air-land-ocean exchange is traditionally hard to model because of the complexity of shoreline environments, which change continually, sculpted by rising sea levels, wind, tides and marine life. To better simulate the process, new models are being developed at NASA’s Goddard Institute for Space Studies. Improved understanding of how carbon moves from land to sea along our coastlines can help scientists construct a more accurate picture of Earth’s carbon cycle overall.