Why in News
A study on coral reef Conducted by the Nature Conservation Foundation and found that Massive Decline in Coral Cover in Lakshadweep (1998–2022). A 50% decline in coral cover in the Lakshadweep archipelago, showing a significant environmental concern.
UPSC Relevance:
CSE in prelims as well as in mains examination has focused on Coral Reef, Symbiotic Relation between different species and coral reef related technology. A case in point is a following PYQ
PYQ Prelims 2022
“Biorock technology” is talked about in which one of the following situations ?
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
Mains PYQ 2019
Assess the impact of global warming on the coral life system with examples.
What is Coral:
Coral are animals from the phylum Cnidaria, typically found along tropical coastlines. They comprise hundreds to thousands of living organisms called polyps, each only a few millimeters in diameter. Each polyp has its own body and a mouth with stinging tentacles to capture food such as plankton and small fish. The polyps grow together until they form a colony, and it is this colony that we recognize as a coral.
Coral Reef:
A coral reef is a term used to describe the collective structure of hard corals that help shape a coral reef ecosystem. A coral reef is a reef whose main structure is made by living organisms.The largest coral reef in the world is Australia’s Great Barrier Reef, which is over 1,000 miles long and covers around 133,000 square miles.
Coral and zooxanthellae: Symbiotic Relation (Mutualism)
Most reef-building corals contain photosynthetic cells called zooxanthellae that live in their tissues. The corals and zooxanthellae have a mutualistic relationship. This means there is a positive relationship between two things and both benefit from the relationship. Corals provide the zooxanthellae with a protected environment, and the coral polyp cells produce carbon dioxide and water that the zooxanthellae need for photosynthesis. The zooxanthellae use energy from the sun to turn the carbon dioxide and water into oxygen and help the coral to remove wastes. Most importantly, zooxanthellae supply the coral with the building blocks of sugars and proteins, which are the products of photosynthesis.
Importance:
- Coral reefs cover only 1% of the ocean floor, but support an estimated 25% of all marine life in the ocean, earning them the moniker ‘rainforest of the sea.’
- Healthy coral reefs play a crucial role in providing coastal protection, habitats for marine life, and even key ingredients for potential new medicines.
- Coral reef ecosystems provide habitat for thousands of species, from unicellular organisms like bacteria or some phytoplankton communities, to large organisms like sharks, groupers or snappers, and reptiles like sea turtles.
- Corals act as a protective barrier during big storm events such as typhoons or hurricanes and have proven to be 97% effective in preventing damage to the natural and built environment.
- Coral can be extracted to create antibiotics that are effective against bacteria resistant to other types of antibiotics.
- Attraction of Tourism.
Coral Reefs are found:
World:
India:
Forest Survey of India Assessment:
Assessment of Coral Reef cover of the following identified Coral Reef
areas in the country using remote sensing and preparation of digital
maps:
i) Andaman & Nicobar Islands
ii) Lakshadweep Islands
iii) Gulf of Mannar (Tamil Nadu)
iv) Gulf of Kutchh (Gujarat)
Angria Bank:
Atoll island located 100 miles off western coast of India.Located off the coast of Ratnagiri & Sindhudurg districts, Maharashtra. This site has potential to be known as India’s Great Barrier Reef.
Types of Coral Reef:
- Fringing reefs grow near the coastline around islands and continents. They are separated from the shore by narrow, shallow lagoons. Fringing reefs are the most common type of reef.
- Barrier reefs also parallel the coastline but are separated by deeper, wider lagoons. At their shallowest points, they can reach the water’s surface forming a “barrier” to navigation.
- Atolls are rings of coral that create protected lagoons and are usually located in the middle of the sea. Atolls usually form when islands surrounded by fringing reefs sink into the sea or the sea level rises around them.
What is coral Bleaching:
When corals are under stress, they expel the microscopic algae that live in their tissues. Without these algae, corals’ tissues become transparent, exposing their white skeleton. This is called coral bleaching. Bleached corals are not dead, but are more at risk of starvation and disease.
Data:
- Coral reefs are some of the most threatened ecosystems on the planet. But there is good news: coral reefs can adapt to global threats if we 1) keep them healthy and reduce local threats, and 2) curb carbon dioxide emissions to slow the pace of climate change.
- 100% of reefs will be threatened by 2050 if we don’t take action now
- 75% of the world’s coral reefs are currently threatened
- 90% of coral reefs will be threatened by 2030
According to a 2020 report produced by the Global Coral Reef Monitoring Network (GCRMN), 14% of the world’s coral reefs have been lost since 2009. In the wake of the 2023-2024 global coral bleaching event, that number is expected to increase.
Causes of Coral Bleaching:
- Increasing ocean temperatures
- Human-caused threat to corals is eutrophication
- Unsustainable Fishing: 55% of the world’s coral reefs are affected by overfishing.
- Land-Based Pollution: 25% of coral reefs around the world are affected by agricultural runoff.
- Sea Level Rise: 200 million people in coastal communities could be displaced if coral growth does not keep up with sea level rise.
- Ocean Acidification: 48% of fossil fuel emissions are absorbed by the ocean. As oceans absorb carbon dioxide (CO2), they become more acidic.
- ENSO
Fourth global mass coral bleaching Event:
The fourth global mass coral bleaching event has been triggered by extraordinary ocean temperatures, the US National Oceanic and Atmospheric Administration. Since mid-March 2023, the average sea surface temperature (SST) has been abnormally high. In March 2023, it reached a record monthly high of 21.07 degree Celsius, according to the EU Copernicus Climate Change Service (C3S). The primary reason behind the soaring temperatures is the rising emissions of heat-trapping greenhouse gases (GHGs) such as carbon dioxide and methane in the atmosphere. Nearly 90% of the extra heat trapped by GHGs has been absorbed by the oceans — that is why they have become so warm.
Protection measures:
The Global Fund for Coral Reefs is a collaborative effort involving private philanthropic organisations and various UN agencies, including UNEP, UNDP, and the UN Capital Development Fund, with a funding target of $500 million. The initiative aims to achieve two primary objectives: first, to promote innovative financing models, particularly those driven by the private sector, for the protection and rehabilitation of coral reefs; and second, to mobilize climate adaptation funding for reef-related projects by tapping into sources such as the Green Climate Fund, the Adaptation Fund, and multilateral development banks.
Bio-rock technology:
The Zoological Survey of India has initiated efforts to restore coral reefs in the Gulf of Kachchh using an innovative method known as Bio-Rock Technology. In this technique, metal frameworks—with coral fragments attached—are placed on the ocean floor. These structures are then supplied with a low-voltage electric current from an external power source. The current encourages dissolved minerals in seawater to accumulate and form calcium carbonate (CaCO₃), which gradually develops into limestone-like formations, providing a stable base for corals to regenerate.
Global Coral Reef Alliance:
GCRA is a coalition of volunteer scientists, divers, environmentalists and other individuals and organizations, committed to coral reef preservation.
Cryomesh Technology
It has been successfully employed by Australian researchers to freeze and preserve coral larvae.Cryomesh system enables storage of the larvae at ultra-low temperatures of -196°C, offering a promising method for long-term conservation of coral species.
