Ecosystem evolution of seal colony and the influencing factors in the 20th century on Fildes Peninsula,West Antarctica

As the topmost predator in Antarctica, the seal is a unique indicator of Antarctic environment and climate changes. In this study, we collected a sediment core from the Fildes Peninsula of West Antarctica, and used cholesterol, cholestanol, epicoprostanol, coprostanol, and seal hair numbers as the proxy indicators of seal population size and phytol as of general vegetation, and we reconstructed the 20th century history of variation of the seal population and vegetation abundance on this island. The sealing industry in the early 20th century caused the dramatic decline of seal population, and the ban of seal hunting since the 1960s led to its recovery of seal population. The seal population during the past century was primarily controlled by human activities and krill density. The reconstructed relation between seal population and vegetation abundance may oifer new insights into Antarctic environment and ecology.     

今后10年我国可欣赏到7次“天狗食日”天象

11月25日天宇将迎来今年第4次日偏食,由于见食区域基本局限在南极洲,因此绝大多数公众都无法观赏。天文专家提示,错过观看此次日偏食的公众也不必遗憾,今后10年内我国公众可欣赏到7次“天狗食日”天象。其中包括两次日全食、三次日环食和两次日偏食。     

极端环境下的生命

想象现在是2030年．地勤人员把你送上了前往火星的宇宙飞船。你的任务就是在这个红色星球上寻找生命。天文学家认为火星和地球在年轻的时候非常相似。还有一些科学家发现地球上的化石表明地球上的生命“仅仅”诞生于10亿年前(而地球到现在则有45亿岁了)。也许火星上也有生命存在。