Question

Collect information about seaweeds sea kelp from your school library and write a note with examples

Answer 1

Hint: Sea kelps are brown algae seaweeds. They are mainly found in shallow layers of the ocean and are rich in phosphorus, potassium and other minerals. Because of their varied characteristics, they are very important for human use.

Complete answer: Sea seaweeds are also called ‘Brown algae’ seaweeds. They are not plants, rather they are heterokont. Heterokonts are organisms that have two flagella of unequal length. Heterokont involves oomycetes, diatoms, chrysophytes and brown algae. Sea kelps are characterized by three main parts as:- blades, stripes and holdfasts; have the following characteristics:
a) Habitat: inhabit shallow layers of the ocean and also coasts of oceans.
b) Nutrition: It derives nutrition by absorption through the body surface.
c) These organisms are known as rainforests of the ocean because of the high level of diversity.
d) They are one of the fastest-growing plants.
e) Ecological role: It provides shelter for fishes such as rockfish and protects many animals against storms.
f) Human use: Kelps are often used as vitamins and a thickening agent in jellies, ice-creams. They are also used as fertilizers and in the production of soaps and cosmetics. It is rich in sodium, potassium, phosphorus and other minerals.
g) Reproduction: They show alternation of generation; the life cycle involves a diploid sporophyte and a haploid gametophyte. Sporophyte releases spores which germinate to produce male and female gametophytes.

Note: Sea kelps belong to the order Laminariales. In most Kelps, the thallus consists of flat or leaf-like structures known as blades. Blades originate from elongated stem-like structures, the stripes. The holdfast, a root-like structure, anchors the kelp to the substrate of the ocean.