沼泽主要是由湖泊演变而来的。由于流入湖泊的河水带着大量泥沙,这些泥沙在湖泊中沉积下来。久而久之,就使得湖泊越来越浅,各种水生植物也随之繁衍起来。泥沙的不断沉积,各种水生植物遗体的不断堆积,于是就形成了泥炭,不断增加的泥炭使湖泊越来越小。最后,湖泊就完全变成了只有 Marsh is evolved mainly from lakes. As the river flows into the lake with a lot of sediment, the sediment deposited in the lake. Over time, it makes the lake more and more shallow, a variety of aquatic plants also will be multiplied. The continuous deposition of sediment, the continuous accumulation of various aquatic plant remains, and thus the formation of peat, the growing peat makes the lake smaller and smaller. In the end, the lake completely turned into the only one