泛滥之谜 19-英语听力

[00:00.01]The soil here is volcanic. [00:02.66]That means it contains a rich cocktail of nutrients. [00:06.29]It was soil as fertile as this which nurtured the crops of Ancient Egypt. [00:11.24]With the plentiful rain and intense mountain sunshine, the grass here grows fast. [00:15.73]This explains why these highlands can support such huge numbers of animals. [00:21.56]The rains are transforming the highlands in another way. [00:27.03]Night temperatures could be low enough to freeze any water in the ground. [00:33.07]As the ice expands, it breaks up the topsoil. [00:38.30]When the ice melts the next morning, the soil is left crumbled and fine. [00:44.63]Millions of nest-making rodents loosen the soil further.