Question

In the vast marine ecosystem, certain seas develop red colouration. This red colour is due to the presence of a large population of which one of the following organisms?
A. Trichodesmium erythraeum
B. Physarum
C. Dinoflagellates
D. Diatoms and members of red algae

Answer 1

Hint: This species was discovered by Captain Cook in 1770. It is a species of cyanobacteria and also known as sea sawdust. This species is visible to the naked eyes.

Complete Answer:
- The word "ecosystem" encompasses much of a natural world that is non-living and living and not limited to water, sunlight, rock, sand, vegetation, bugs and wildlife. Marine environments are coastal environments with a high salt concentration in their waters.
- Sea habitats are the most common of all forms of ecosystems on the planet. It blossoms in life, supplying a vast variety of animals with almost half the earth's oxygen. The biological community of the related species, and their physical environment, is typical of marine ecosystems.
- Trichodesmium erythraeum is a unique creature of Cyanobacteria that can be seen to the naked eye. It was first found on the coast of Australia by Captain Cook in 1770. The Red Sea discoloration during flowering is caused by Trichodesmium erythraeum.
- Though it is a blue green alga, it has a red pigment, phycoerythrin, which gives the water of the sea a red colour, hence the named Red Sea. They are present in low nutrient tropical and subtropical ocean waters.

Thus, the correct answer is option A. i.e., Trichodesmium erythraeum.

Note: Marine ecosystems are the largest in the world and are characterized by water with a high concentration of salt. Marine waters span over 70 % of the surface and represent over 97% of the world's source of water and 90% of the Earth's ecosystem.