on an unprecedented scale. 规模空前

346. But now, they would almost bring it to an end.
     但是现在 它几乎将动物生命带入终结
347. A sudden surge in ocean nutrients
     海洋养分激增
348. caused the population of plankton to increase...
     导致浮游生物数量增加
349. on an unprecedented scale.
     规模空前
350. As it spread through the sunlit shallows,
     当浮游生物遍布阳光照耀的浅水时
351. this thick soup began to rot...
     这浓汤般的水体开始腐烂
352. causing the ocean's oxygen to plummet.
     导致海洋中的氧骤减

来自《我们星球上的生命 第一季 第二集 Life on Our Planet S01E02 第一前线》第 349 行