Layer of scum的意思|示意

The algal blooms, which can be toxic to animals and human swimmers, leave behind an ugly layer of green scum that fouls tourist beaches and starves seaweeds of light.

海面上的赤潮对水里的动物和游泳的人来说都是有毒性的，赤潮藻还会在海面上留下一层难看的绿色浮渣，不但污染了供人旅游的海岸，还遮挡了海草的光线，使其不能生长。

In the scum layer, these fatty materials may be rather remote from the bacteria that are capable of utilizing them.

泡沫层中的脂肪物质离能利用脂肪的细菌相当远。