Algal (adjective)

1. Of or relating to algae.
2. Consisting of or containing algae.

Origin:

Mid 19th century: from alga + -al.

Examples:

1. Algal blooms in the lake caused the water to turn green.
2. The algal mats covered the rocks in the stream.
3. Algal growth on the pond's surface reduced the amount of sunlight reaching the plants below.
4. The algal cells are the basic unit of life in kelp.
5. Algal fossils are used to study the history of life on Earth.