Professor Cardenas says his recent study shows that more than 99 percent of the river's water does pass through the river's sediment which is on the shore or bottom of the river. But he says the study found that there is so much nitrogen in the river system that is simply can not filter all of it. Cardenas教授表示,他最近的研究显示,超过99%的河水确实会流经岸边或河底的沉积物.但他表示,该研究发现,河水的含氮量是很高的,根本无法被完全过滤掉. The water that has nitrogen still in it supports the growth of algae. 含氮的河水帮助藻类植物的生长. ______________________
