摘要
科学家们说世界上的海洋正在慢慢变酸，他们称这种变化是由于大气中二氧化碳含量过高造成的。他们警告说，目前海水pH值下降还不是非常严重，但是如果继续下降的话，将对现存的海洋生物造成严重的威胁。
The world＇s oceans are slowly getting more acidic, say scientists. They say the change is taking place in response to higher levels of carbon dioxide in the atmosphere. The lowering of the waters＇ pH value is not great at the moment, but could pose a serious threat to current marine life if it continues, they warn.
