Question

The marine plant living at different depths of the ocean are adapted to survive
A. In the UV component of solar radiation
B. Without any component of the solar spectrum
C. In only some components of solar radiation
D. By using a chemical source of energy for photosynthesis

Answer 1

Hint: Deep regions of the ocean are dark as a negligible amount of sunlight reaches there. The ocean is divided into three zones depending on the depth and availability of light namely euphotic, disphotic and aphotic zone.

Complete step by step answer: Marine plants and animals living at different depths of ocean constitute the marine ecosystem and these regions do not get adequate sunlight and these plants are adapted to survive the UV component of solar radiations. In the case of deep-sea dwellers, sunlight is inadequate for photosynthesis. The deepest region of the ocean is entirely dark. Plants like Kelps, seagrasses and seaweed live in deep-sea regions. The intensity of light is highest at the surface and decreases as we move more deep inside the ocean but these marine plants at different depths are adapted to survive using UV components of solar radiation.
Hence, the correct answer is option A.

Additional information: Ocean is divided into three zones according to depth and availability of light. Euphotic or sunlight zone: upper 200 metres of the ocean, and it is home to a vast variety of aquatic species. Twilight zone or disphotic zone: 200-1000 metres. The sunlight decreases as depth increases. Photosynthesis is very less possible in this zone and Aphotic zone: Below 1000 metres. There is no sunlight, it’s complete darkness.

Note: Plants, animals and some algae inhabiting the deepest regions of oceans where no sunlight is present, are able to survive due to the adaptations that help them to utilize the UV component of sunlight. Also, blue light penetrates deep inside the ocean because of its low wavelength.