This ecosystem is one of the fascinating paradoxes of the biosphere: how do clear, and thus nutrient-poor, waters support such prolific and productive communities?

这个生态系统是生物圈中令人着迷的悖论之一：清澈而又缺乏营养的水域是如何支撑如此多产的群落的？

Recently planetary scientists have suggested that the external preconditions for the development of Earth's biosphere probably included four paramount contingencies.

最近，行星科学家提出，地球生物圈发展的外部先决条件可能包括四个最重要的偶发事件。

Biocycle is the cycling of chemicals through the biosphere.

生物循环是化学物质在生物圈内的循环。