To see how biofilms come about, let's watch one as it develops on a submerged river rock.

为了了解生物膜如何产生，我们以一个生长在河石上的生物膜为例。

The submerged rock would chemically take in carbon from the water.

淹没的岩石会通过化学方式从水中吸收碳。

For archaeologists in Spain, this summer's drought has meant a rare chance to study the normally submerged rock formation known as the Spanish Stonehenge.

对于西班牙的考古学家来说，今年夏天的干旱意味着一个难得的机会--研究被称为西班牙巨石阵的水下岩层。