1. Corals get the credit for most of the reef structure, but much of the construction is done by fast-growing, encrusting red algae.
珊瑚因大部分礁石结构而得名，但很大一部分建筑工作是由快速生长的成薄壳状红藻完成的。
2. The sea urchin, in water, gnaws away at encrusting algae.
海胆在啃食身体外的藻类植物。