七里海泻湖的形成与演变

七里海泻湖位于渤海湾的西北岸，是全新世晚期的一个半封闭泻湖。在其演变过程中至少经历过两次由泻湖──淡水湖──泻湖的过程。水体及湖体性质的变化决定于其是否与海连通及河流注入情况。近期，受人类经济活动及工程的影响，七里海泻湖生态系统遭到严重的破坏，并加速了泻湖的退化和消亡。

ON THE FORMATION AND EVOLUTION OF THE QILIHAI LAGOON

The Qilihai Lagoon is locatcd at the northern coast of Bohai Bay. It is a semienclosed lagoon. Five small streams empty into it. In the later period of the Holocene, along with marine regrcssion the Qilihai Lagoon had eyolved from barrier-barlagoon. In the historical period, it was enclosed by costal dune at least two times.When it was enclosed, it turned into a fresh water lake, In this very period thearea of the lake expanded. In 1883, as the coastal dune enclosing the lagoon wasbursted by the flood of the Luanhe River, the Qilihai lagoon had changed into alagoon too. At present, the lagoon ecosystem is distroyed by man's economic andengineering actvities. The lagoon is being on the wane.