5.6

5-6 Water Stands in Some Freshwater Systems and Flows in Others有什麼主要類型的淡水系統和我們怎樣影響它們?
答: 淡水系統主要有湖泊、池塘、內陸濕地和流動系統像是溪流和河。
人類對淡水系統的影響主要有四個途徑:水壩和運河分散於世界273條大河流約40%，它們改變及破壞陸地和水中野生動物的棲息地，藉由降低水流量和增加海岸暴風雨的危害,沿著河流建造用來阻擋洪水的堤防破壞水生生物的棲地,城市和農地的汙染物超過鄰近溪流、河和湖中的植物營養物,許多內陸濕地被填滿用來種植作物或覆蓋混凝土、柏油和建築物。
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CONCEPT 5-6 Human activits are impairing ecological and economic services provided by many rivers and
freshwater lakes and wetlands.
這章是講述人類的活動損害生態和經濟服務。



Freshwater life zones include standing bodies of freshwater, such as lakes, ponds,
and inland wetlands, and flowing systems, such as streams and rivers. Although these freshwater
systems cover only about 2.2% of the earth's surface, they provide a number of important
ecological and economic services.
bad news: humanactivities are disrupting and degrading many of the ecological and economic services provided by the world's freshwater rivers, lakes,
and wetlands.
淡水的區域主要包括有湖泊、池塘和沼澤，而流動的系統有小溪和河流。雖然這些淡水系統覆蓋地球表面只有2.2%，但他們提供了許多重要的生態系統和經濟服務(圖5-28)。
壞消息:人的活動導致地球淡水湖泊、河流和沼澤供應的生態和經濟服務中斷和降低。

重點: 淡水系統分別有河流、湖泊、沼澤、池塘和小溪；而水存在於一些淡水系統和其他的流動區域。
人類的活動損害生態和經濟服務。



Lakes Are Depressions Filled with Freshwater
湖泊是充滿淡水的凹地
Lakes are large natural bodies of standing freshwater formed when precipitation, runoff, of groundwater seepage fills depressions in the earth’s surface. Causes of such depressions include glaciation (the great lakes of north America), crustal displacement (lake Nyasa in East Africa),and volcanic activity (crater Lake in the U.S state of Oregon). Lakes are supplied with water from rainfall, melting snow, and streams that drain their surrounding watershed
湖泊是淡水的一種型態，它是大自然的主要部分當降雨、淨流、地下水滲出裝滿陸地表面的凹地形成的。
凹地形成的原因包括冰河作用(北美的大湖)，地殼移位(在東非的Nyasa湖)，和火山運動(美國俄勒岡州的火山河口湖)。
湖泊的水來自降雨、融化的雪和河流，流出他們周圍的流域。

重點: 介紹湖泊是怎樣形成的