Freshwater
淡水

It amounts to precious little water, less than half a percent of the world's water supply. Yet it is vital to the survival of humans and a wide range of critters from dragonflies and piranhas to beavers and bullfrogs.

淡水等于珍贵而量少的水，不到全球水量供给的一半。不过，它对于人类的和家畜的生存是必要的，从蜻蜓和水虎鱼到海狸和牛蛙都离不开它。

Lakes and ponds are basins of water surrounded by land, whereas rivers and streams are the arteries that move freshwater from land, such as mountain peaks, to the oceans. At the edge of many lakes and rivers are saturated wetlands—the swamps, bogs, and marshes—that support myriad types of plant and animal life, prevent floods, retain sediments, and purify drinking water. All the freshwater ecosystems can be found within a watershed—a set of habitats that drain into a single body of water such as a big lake or the ocean.

湖泊和池塘是被陆地环绕的水盆，而河流和溪水是陆地上淡水流动的要道，比如从山峰到海洋。湖泊和河流的边缘是湿润的沼泽地带——沼泽，泥沼和湿地，它们支撑着无数种动植物的生命，防止洪水，保留沉积物，并且净化饮用水。所有的淡水生态系统都能在水域中找到，一套栖息地流失成一个单一的水体,比如一个大的湖泊或海洋 。

From scum on ponds to water celery on river beds and reeds swaying in a wetland breeze, freshwater algae and plants provide oxygen to breathe and food to eat. Plants like duckweeds float on the surface of still and slow-moving waters, while those with roots and flexible stems can stand in swift-flowing streams. Wetlands are full of vegetation that feeds everything from fish to people. In fact, about half the world's human population depends on rice, a wetland plant.

从池塘的浮渣到河床上的水芹，以及沼泽微风中摇摆的芦苇，淡水藻类和植物提供呼吸之用的氧气和食用的食物。从漂浮在静止或者缓慢流动的水面上的浮萍，到位于激之流中的长着根和柔软茎的植物。湿地上长满了可以供从鱼到人等各种生物食用的植被。实际上，全球大约一半的人口靠一种湿地作物稻米生活。