Context:
Largest deep-sea coral reef have been mapped by scientists off the US Atlantic coast
Difference between Deep sea and Shallow water corals:
| Deep Sea Corals | Shallow Water Corals | |
| Location | Found in deep water | Found in high-light, shallow, clear waters |
| Nutrition | Filter particles out of the water column | Rely on photosynthesis |
| Growth Rate | Slow growth rate and a longer recovery period | Fast growth rate and a shorter recovery period |
| Sunlight Requirement | Don’t need sunlight | Require light for the symbiotic organisms in their tissues to photosynthesize |
| Relationship with Algae | Don’t have a symbiotic relationship with algae | Have a symbiotic relationship with algae called zooxanthellae |
Corals:
- Marine invertebrates
- Called the “rainforests of the seas”.
- Made up of genetically identical organisms called polyps.
- The tissues of these polyps contain microscopic algae known as zooxanthellae.
- Thousands of such polyps live together to form a colony, which grow when polyps multiply to make copies of themselves.
- Mutualistic relationship between corals and algae –
- Corals – Supply compounds for photosynthesis to the zooxanthellae.
- Zooxanthellae – Supply the coral with organic products of photosynthesis which are utilized by the coral polyps for synthesis of their calcium carbonate skeletons.
- Zooxanthellae are responsible for the unique and beautiful colors of corals.
- Favourable Conditions –
- Warm tropical oceans with minimum temperature of 20° C (30° N and 25° S latitudes)
- Oceanic water free of sedimentation
- Transparent parts of ocean bodies
- Relatively low salinity ocean bodies
- Types – Fringing reefs, Barrier reefs, Atolls
- Distribution in India –
- Gulf of Kutch
- Inter tidal areas on the West Coast of India
- Lakshadweep Islands (Atolls)
- Gulf of Mannar
- Palk Bay
- Andaman & Nicobar Islands
Coral Bleaching: When corals are stressed by changes in conditions such as temperature, light, or nutrients, they expel the symbiotic algae (zooxanthellae) living in their tissues, causing them to turn completely white.
Source: Times of India
Previous Year Question
“Biorock technology” is talked about in which one of the following situations?
[UPSC Civil Services Exam – 2022 Prelims]
(a) Restoration of damaged coral reefs
(b) Development of building materials using plant residues
(c) Identification of areas for exploration/extraction of shale gas
(d) Providing salt licks for wild animals in forests/protected areas
Answer: (a)
