Question

Sea lettuce is the common name for
a. Laminaria
b. Fucus
c. Sargassum
d. Ulva

Answer 1

All the options given above belong to the algae family. For an algae to be called ‘sea lettuce’, it should be possessing physical characteristics similar to that of lettuce.

Complete answer:
In the options given above, laminaria, fucus and sargassum are brown algae while ulva is the only green algae. Hence, ulva is commonly known as ‘sea lettuce’ as they possess green thin and broad leaf like structure with coarse edges.

Hence, the correct answer is option (D).

Additional information:
Let us look at the characteristics of other algae:

Laminaria – This is a type of brown algae and is commonly referred to as kelp. They are found under the water creating a habitat for the fishes. They are of great economic value as they are edible, their extracts have great medicinal value and can be used for metal absorption. They are also studied as a potential source of biofuel.

Fucus – This brown algae can be predominantly found in the intertidal rocky seashore. They are used in thalassotherapy (therapy with seaweeds) and as fertilizers. Since they are on the shores, they are the habitat for the seaweed flies.

Sargassum – They are brown or dark green coloured algae which can be seen in shallow waters and coral reefs. They are also found to float on the water surface for which it is equipped with small bulb-like structures for photosynthesis. Sargassum are vital to small marine organisms as they use this algae for camouflage or to cover themselves from predators.

Note: Ulva are edible as they are nutritious with a high amount of iron. These algae can be washed to the shore which might possess a huge health hazard. This decomposition released toxic fumes such as hydrogen cyanide and hydrogen sulphide which resulted in the death of humans and few organisms around it.