经济学人下载:海中劲草(1)

Carbon capture and storage 

碳捕获与存储技术

Supergrass 

劲草

Plants in the ocean are better at storing carbon than those on land 

海洋植物比陆地植物更善于储存碳

Off the coast of Formentera, an island in the Spanish Mediterranean, lives an organism that stretches 15km from one end to the other. Posidonia oceanica, more prosaically known as seagrass, spreads by sending shoots out beneath the sediment. Entire meadows, covering several hectares, can thus be made up of a single organism. The grasses are long-lived, too. The vast meadow in Formentera is thought to have been spreading for tens or hundreds of thousands of years. 

西班牙地中海的福门特拉岛海岸生活着一种有机体，这种有机体从一端延伸到另一端的长度达15公里。波西多尼亚水生植物，通俗点儿讲叫海草。它通过在沉积物下发射嫩芽进行繁殖，因此就连覆盖数公顷的整片海草都是由单一有机体组成。这些草也很长寿。福门特拉广阔的海草床据悉已经蔓延了数万年甚至数十万年。

But the seagrass is more than just a biological curiosity. Along with two other kinds of coastal ecosystem—mangrove swamps and tidal marshes—seagrass meadows are particularly good at taking carbon dioxide from the air and converting it into plant matter. That makes all three ecosystems important for efforts to control climate change. 

但海草不仅是一种奇特的生物。海草床，还有另外两种沿海生态系统——红树林沼泽和潮汐沼泽，尤其擅长从空气中吸收二氧化碳并将其转化为植物物质。这使得这三个生态系统对于控制气候变化都很重要。

This role was highlighted in a report published on March 2nd by UNESCO, an arm of the United Nations, on "blue carbon"—the sort captured by Earth's oceanic and coastal ecosystems. In total around 33bn tonnes of carbon dioxide (about three-quarters of the world's emissions in 2019) are locked away in the planet's bluecarbon sinks. Research by Carlos Duarte, the report's author and a marine ecologist at King Abdullah University in Saudi Arabia, has shown that one hectare of seagrass can soak up as much carbon dioxide each year as 15 hectares of rainforest. 

联合国教科文组织3月2日发布的一份关于“蓝碳”(地球海洋和沿海生态系统所捕获的碳)的报告中强调了这种作用。总共约有330亿吨二氧化碳(约占2019年全球排放量的四分之三)被锁在地球的蓝碳汇中。该报告的作者、沙特阿拉伯阿卜杜拉国王大学海洋生态学家卡洛斯·杜阿尔特的研究表明，一公顷海草每年吸收的二氧化碳相当于15公顷雨林。

All this is attracting interest in blue carbon from those keen to use natural processes, rather than human technologies such as direct-air capture, to suck greenhouse gases from the atmosphere. In 2018 Apple partnered with Conservation International, a charity, to protect 11,000 hectares of mangroves on the Colombian coast. The firm estimates the project could lock away around 1m tonnes of carbon. 

所有这些都吸引了那些热衷于利用自然过程而不是人类技术(如直接捕获空气)从大气中吸收温室气体的人对蓝碳的兴趣。2018年，苹果公司与慈善机构保护国际合作，保护了哥伦比亚海岸1.1万公顷的红树林。该公司估计，该项目可以储存约100万吨碳。

One reason that blue-carbon ecosystems make such effective sinks is that submerged forests are denser than their landbased equivalents. They can also trap floating debris and organic matter, which settles on the sea floor and can double the amount of carbon stored away. 

蓝碳生态系统之所以会产生如此巨大的碳汇，其中一个原因是水下森林比陆上森林密度更大。它们还能捕获漂浮在海底的碎片和有机物，使碳的储存量增加一倍。